diff --git a/GameData/RP-1/Tree/ECM-Engines.cfg b/GameData/RP-1/Tree/ECM-Engines.cfg
index 2a6b4187e2..fcd63b68f8 100644
--- a/GameData/RP-1/Tree/ECM-Engines.cfg
+++ b/GameData/RP-1/Tree/ECM-Engines.cfg
@@ -74,6 +74,7 @@
     ALCE = 250000,RS-25D-E
     AMBR-623N = 5000,NTOOxidizer,HydrazineFuel
     AR-1 = 27000,StagedKerolox
+    AR-2 = 5000,XLR42-NA-2
     AR-22 = 50000,RS-25D-E
     ASCENT = 5544,CatalystRCS
     ASRB = 0
@@ -231,7 +232,7 @@
     ISPS = 5000,Model8250,ElectricPumps
     ISPS-HDA = ISPS
     Isayev-R17 = 5000, S5-2
-    J-2-200K = 225000, HydroloxPumps, Navaho-TP
+    J-2-200K = 225000, HydroloxPumps, Navaho-TP, throttlingTP, PumpReignition
     J-2-225K = 20000, J-2-200K
     J-2-230K = 5000, J-2-225K
     J-2S = 80000, J-2
@@ -321,6 +322,7 @@
     LR105-NA-6 = 3000, Navaho-TP-1962, LR105-NA-5
     LR105-NA-7-1 = 1200, MA-5-System, LR105-NA-6
     LR105-NA-7-2 = 1200, MA-5-System-I, LR105-NA-7-1
+    LR121-NA-1 = 5000,PumpReignition,throttlingTP
     LR129-P-1 = 32474,XLR129-P-1
     LR129-P-2 = 173267,LR129-P-1
     LR129-P-3 = 25000,LR129-P-2
@@ -646,7 +648,7 @@
     RJ43-MA-3 = 7500
     RJ43-MA-5 = 5000,RJ43-MA-3
     RL100 = 50000,RL10A-3-3A
-    RL10A-1 = 37549, HydroloxPumps
+    RL10A-1 = 37549, HydroloxPumps, PumpReignition
     RL10A-3-1 = 15000, RL10A-1
     RL10A-3-3 = 20000, RL10A-3-1
     RL10A-3-3A = 25000,RL10A-3-3
@@ -719,7 +721,7 @@
     Rubis = 0
     Rutherford-SL = 15000, ElectricPumps
     RutherfordVac = 5000, Rutherford-SL
-    S-155 = 10000, Wasserfall
+    S-155 = 10000,Wasserfall,throttlingTP,PumpReignition
     S-3 = 23000, Navaho-TP
     S-3D = 2000, Navaho-TP-1958, S-3
     S-3FH = 5000,S-3D,Navaho-TP-1962,HydrazineFuel
@@ -877,9 +879,10 @@
     XLR11-RM-5 = 5000,XLR11-RM-3
     XLR129-P-1 = 428298,StagedHydrolox
     XLR132 = 50000,HypergolicPumps,PumpReignition
-    XLR25-CW-1 = XLR11-RM-5, 5000
+    XLR25-CW-1 = 5000,XLR11-RM-5,throttlingTP,PumpReignition
     XLR35-RM-1 = 8000,XLR11-RM-5
     XLR41 = Navaho-PhaseII-TP
+    XLR42-NA-2 = 10000
     XLR43-NA-1 = 5000, Navaho-PhaseIII-TP
     XLR43-NA-3 = 5000,Navaho-PhaseIV-TP
     XLR81-BA-11 = Model8096
@@ -888,8 +891,9 @@
     XLR81-BA-5 = Model8048
     XLR81-BA-7 = Model8081
     XLR81-LF2-SPS = 80000,Model8096
-    XLR99-RM-2 = 50000, XLR11-RM-3
+    XLR99-RM-2 = 50000, XLR11-RM-3,throttlingTP,PumpReignition
     XLR99-RM-2A = 5000,XLR99-RM-2
+    XLR99-RM-3 = 50000,XLR99-RM-2A
     XM-20 = 6000, SergeantDev
     XRJ47-W-5 = 10000,RJ43-MA-3
     XRJ55-W-1 = 5000,XRJ47-W-5
diff --git a/GameData/RP-1/Tree/ECM-Parts.cfg b/GameData/RP-1/Tree/ECM-Parts.cfg
index 8b676fa9f1..d94514a1c4 100644
--- a/GameData/RP-1/Tree/ECM-Parts.cfg
+++ b/GameData/RP-1/Tree/ECM-Parts.cfg
@@ -706,6 +706,7 @@
     ROE-AJ260SLF = AJ260-SL1
     ROE-AJ260SLF-BDB = AJ260-SL1
     ROE-AJ60 = AJ-60A
+    ROE-AR2 = XLR42-NA-2
     ROE-Aerobee = WAC-Corporal
     ROE-Aerobee-Taerobee = WAC-Corporal
     ROE-Agena = Model117
diff --git a/GameData/RP-1/Tree/TREE-Engines.cfg b/GameData/RP-1/Tree/TREE-Engines.cfg
index 559659d9d4..e159dfa0bc 100644
--- a/GameData/RP-1/Tree/TREE-Engines.cfg
+++ b/GameData/RP-1/Tree/TREE-Engines.cfg
@@ -453,6 +453,14 @@
                 %cost = 0
             }
 
+            @CONFIG[AR-2]
+            {
+                %techRequired = orbitalRocketry1959
+                %cost = -6
+                tag = EngineLiquidPF
+                *@PARTUPGRADE[RFUpgrade_AR-2]/deleteme -= 1
+            }
+
             @CONFIG[AR-22]
             {
                 %techRequired = FRSC2019
@@ -2068,6 +2076,14 @@
                 *@PARTUPGRADE[RFUpgrade_LR105-NA-7.2]/deleteme -= 1
             }
 
+            @CONFIG[LR121-NA-1]
+            {
+                %techRequired = orbitalRocketry1963
+                %cost = -4
+                tag = EngineLiquidTurbo
+                *@PARTUPGRADE[RFUpgrade_LR121-NA-1]/deleteme -= 1
+            }
+
             @CONFIG[LR129-P-1]
             {
                 %techRequired = FRSC1976
@@ -5763,6 +5779,13 @@
                 %description = Americanized version of the V-2 Model 39 (A-4). It was very similar to its predecessor, but was built using American SAE components rather than Metric components, and featured several minor upgrades.
             }
 
+            @CONFIG[XLR42-NA-2]
+            {
+                %techRequired = orbitalRocketry1956
+                %cost = 0
+                tag = EngineLiquidPF
+            }
+
             @CONFIG[XLR43-NA-1]
             {
                 %techRequired = earlyRocketry
@@ -5828,7 +5851,15 @@
             @CONFIG[XLR99-RM-2A]
             {
                 %techRequired = orbitalRocketry1962
-                %cost = 50
+                %cost = 10
+                *@PARTUPGRADE[RFUpgrade_XLR99-RM-2A]/deleteme -= 1
+            }
+
+            @CONFIG[XLR99-RM-3]
+            {
+                %techRequired = orbitalRocketry1966
+                %cost = 27
+                *@PARTUPGRADE[RFUpgrade_XLR99-RM-3]/deleteme -= 1
             }
 
             @CONFIG[XM-20]
@@ -7391,6 +7422,46 @@ PART
 {
 }
 
+PARTUPGRADE
+{
+        name = RFUpgrade_AR-2
+        partIcon = RO-H1-RS27 // FIXME Once we get dedicated model
+        techRequired = orbitalRocketry1959
+        entryCost = 0
+        cost = 0      
+        title = AR2 Engine Upgrade: AR-2 Config
+        basicInfo = Engine Performance Upgrade
+        manufacturer = Engine Upgrade
+        deleteme = 1
+        description = The AR2 Engine now supports the AR-2 configuration for increased performance. Unlock it in the VAB/SPH through the engine configs interface.\n\n
+}
+
+PART
+{
+    name = RFUpgrade_engineConfigSource_AR-2
+    engineType = AR2
+}
+
+@PART[RFUpgrade_engineConfigSource_AR-2]:AFTER[RealismOverhaulEngines]
+{
+    %MODULE[Module*EngineConfigs] {
+        @name = ModuleEngineConfigs
+        %CONFIG[AR-2] {
+            &specLevel = operational
+        }
+    }
+}
+
+@PARTUPGRADE[RFUpgrade_AR-2]:AFTER[RealismOverhaulEngines]
+{
+    %description = #$description$\nAvailable at specLevel $@PART[RFUpgrade_engineConfigSource_AR-2]/MODULE[ModuleEngineConfigs]/CONFIG[AR-2]/specLevel$
+    // TODO: could add any number of other useful fields from the CONFIG here. cost? description?
+}
+
+!PART[RFUpgrade_engineConfigSource_AR-2]:AFTER[RealismOverhaulEngines]
+{
+}
+
 PARTUPGRADE
 {
         name = RFUpgrade_ASCENT
@@ -12591,6 +12662,46 @@ PART
 {
 }
 
+PARTUPGRADE
+{
+        name = RFUpgrade_LR121-NA-1
+        partIcon = RO-H1-RS27 // FIXME Once we get dedicated model
+        techRequired = orbitalRocketry1963
+        entryCost = 0
+        cost = 0      
+        title = AR2 Engine Upgrade: LR121-NA-1 Config
+        basicInfo = Engine Performance Upgrade
+        manufacturer = Engine Upgrade
+        deleteme = 1
+        description = The AR2 Engine now supports the LR121-NA-1 configuration for increased performance. Unlock it in the VAB/SPH through the engine configs interface.\n\n
+}
+
+PART
+{
+    name = RFUpgrade_engineConfigSource_LR121-NA-1
+    engineType = AR2
+}
+
+@PART[RFUpgrade_engineConfigSource_LR121-NA-1]:AFTER[RealismOverhaulEngines]
+{
+    %MODULE[Module*EngineConfigs] {
+        @name = ModuleEngineConfigs
+        %CONFIG[LR121-NA-1] {
+            &specLevel = operational
+        }
+    }
+}
+
+@PARTUPGRADE[RFUpgrade_LR121-NA-1]:AFTER[RealismOverhaulEngines]
+{
+    %description = #$description$\nAvailable at specLevel $@PART[RFUpgrade_engineConfigSource_LR121-NA-1]/MODULE[ModuleEngineConfigs]/CONFIG[LR121-NA-1]/specLevel$
+    // TODO: could add any number of other useful fields from the CONFIG here. cost? description?
+}
+
+!PART[RFUpgrade_engineConfigSource_LR121-NA-1]:AFTER[RealismOverhaulEngines]
+{
+}
+
 PARTUPGRADE
 {
         name = RFUpgrade_LR129-P-1
@@ -24550,3 +24661,83 @@ PART
 !PART[RFUpgrade_engineConfigSource_XLR81-LF2-SPS]:AFTER[RealismOverhaulEngines]
 {
 }
+
+PARTUPGRADE
+{
+        name = RFUpgrade_XLR99-RM-2A
+        partIcon = RO-H1-RS27 // FIXME Once we get dedicated model
+        techRequired = orbitalRocketry1962
+        entryCost = 0
+        cost = 0      
+        title = XLR99 Engine Upgrade: XLR99-RM-2A Config
+        basicInfo = Engine Performance Upgrade
+        manufacturer = Engine Upgrade
+        deleteme = 1
+        description = The XLR99 Engine now supports the XLR99-RM-2A configuration for increased performance. Unlock it in the VAB/SPH through the engine configs interface.\n\n
+}
+
+PART
+{
+    name = RFUpgrade_engineConfigSource_XLR99-RM-2A
+    engineType = XLR99
+}
+
+@PART[RFUpgrade_engineConfigSource_XLR99-RM-2A]:AFTER[RealismOverhaulEngines]
+{
+    %MODULE[Module*EngineConfigs] {
+        @name = ModuleEngineConfigs
+        %CONFIG[XLR99-RM-2A] {
+            &specLevel = operational
+        }
+    }
+}
+
+@PARTUPGRADE[RFUpgrade_XLR99-RM-2A]:AFTER[RealismOverhaulEngines]
+{
+    %description = #$description$\nAvailable at specLevel $@PART[RFUpgrade_engineConfigSource_XLR99-RM-2A]/MODULE[ModuleEngineConfigs]/CONFIG[XLR99-RM-2A]/specLevel$
+    // TODO: could add any number of other useful fields from the CONFIG here. cost? description?
+}
+
+!PART[RFUpgrade_engineConfigSource_XLR99-RM-2A]:AFTER[RealismOverhaulEngines]
+{
+}
+
+PARTUPGRADE
+{
+        name = RFUpgrade_XLR99-RM-3
+        partIcon = RO-H1-RS27 // FIXME Once we get dedicated model
+        techRequired = orbitalRocketry1966
+        entryCost = 0
+        cost = 0      
+        title = XLR99 Engine Upgrade: XLR99-RM-3 Config
+        basicInfo = Engine Performance Upgrade
+        manufacturer = Engine Upgrade
+        deleteme = 1
+        description = The XLR99 Engine now supports the XLR99-RM-3 configuration for increased performance. Unlock it in the VAB/SPH through the engine configs interface.\n\n
+}
+
+PART
+{
+    name = RFUpgrade_engineConfigSource_XLR99-RM-3
+    engineType = XLR99
+}
+
+@PART[RFUpgrade_engineConfigSource_XLR99-RM-3]:AFTER[RealismOverhaulEngines]
+{
+    %MODULE[Module*EngineConfigs] {
+        @name = ModuleEngineConfigs
+        %CONFIG[XLR99-RM-3] {
+            &specLevel = operational
+        }
+    }
+}
+
+@PARTUPGRADE[RFUpgrade_XLR99-RM-3]:AFTER[RealismOverhaulEngines]
+{
+    %description = #$description$\nAvailable at specLevel $@PART[RFUpgrade_engineConfigSource_XLR99-RM-3]/MODULE[ModuleEngineConfigs]/CONFIG[XLR99-RM-3]/specLevel$
+    // TODO: could add any number of other useful fields from the CONFIG here. cost? description?
+}
+
+!PART[RFUpgrade_engineConfigSource_XLR99-RM-3]:AFTER[RealismOverhaulEngines]
+{
+}
diff --git a/GameData/RP-1/Tree/TREE-Parts.cfg b/GameData/RP-1/Tree/TREE-Parts.cfg
index f48eed01a2..4c8c7d3f4c 100644
--- a/GameData/RP-1/Tree/TREE-Parts.cfg
+++ b/GameData/RP-1/Tree/TREE-Parts.cfg
@@ -7222,7 +7222,7 @@
 @PART[RO-XLR99]:FOR[xxxRP0]
 {
     %TechRequired = orbitalRocketry1959
-    %cost = 315
+    %cost = 333
     %entryCost = 0
     RP0conf = true
     @description ^=:$: <b><color=green>From Stock (RO Config) mod</color></b>
@@ -10031,6 +10031,17 @@
 
     %MODULE[ModuleTagList] { tag = EngineSolid }
 
+}
+@PART[ROE-AR2]:FOR[xxxRP0]
+{
+    %TechRequired = orbitalRocketry1956
+    %cost = 91
+    %entryCost = 0
+    RP0conf = true
+    @description ^=:$: <b><color=green>From ROEnginesExtended mod</color></b>
+
+    %MODULE[ModuleTagList] { tag = EngineLiquidTurbo }
+
 }
 @PART[ROE-Aerobee]:FOR[xxxRP0]
 {
@@ -13234,7 +13245,7 @@
 @PART[ROE-XLR99]:FOR[xxxRP0]
 {
     %TechRequired = orbitalRocketry1959
-    %cost = 315
+    %cost = 333
     %entryCost = 0
     RP0conf = true
     @description ^=:$: <b><color=green>From ROEngines mod</color></b>
@@ -13934,7 +13945,7 @@
 @PART[ROEE-XLR99A]:FOR[xxxRP0]
 {
     %TechRequired = orbitalRocketry1962
-    %cost = 315
+    %cost = 333
     %entryCost = 0
     RP0conf = true
     @description ^=:$: <b><color=green>From ROEnginesExtended mod</color></b>
diff --git a/Source/Tech Tree/Parts Browser/data/Engine_Config.json b/Source/Tech Tree/Parts Browser/data/Engine_Config.json
index bdafa717e8..69a467c414 100644
--- a/Source/Tech Tree/Parts Browser/data/Engine_Config.json	
+++ b/Source/Tech Tree/Parts Browser/data/Engine_Config.json	
@@ -1414,6 +1414,29 @@
         "identical_part_name": "",
         "module_tags": []
     },
+    {
+        "name": "AR-2",
+        "title": "AR-2",
+        "description": "",
+        "mod": "Engine_Config",
+        "cost": "-6",
+        "entry_cost": "0",
+        "category": "ORBITAL",
+        "info": "",
+        "year": "1959",
+        "technology": "orbitalRocketry1959",
+        "ro": true,
+        "orphan": false,
+        "rp0_conf": true,
+        "spacecraft": "",
+        "engine_config": "AR2",
+        "upgrade": true,
+        "entry_cost_mods": "5000,XLR42-NA-2",
+        "identical_part_name": "",
+        "module_tags": [
+            "EngineLiquidPF"
+        ]
+    },
     {
         "name": "AR-22",
         "title": "AR-22",
@@ -4881,7 +4904,7 @@
         "spacecraft": "Saturn V",
         "engine_config": "J2",
         "upgrade": false,
-        "entry_cost_mods": "225000, HydroloxPumps, Navaho-TP",
+        "entry_cost_mods": "225000, HydroloxPumps, Navaho-TP, throttlingTP, PumpReignition",
         "identical_part_name": "",
         "module_tags": []
     },
@@ -6841,6 +6864,29 @@
         "identical_part_name": "",
         "module_tags": []
     },
+    {
+        "name": "LR121-NA-1",
+        "title": "LR121-NA-1",
+        "description": "",
+        "mod": "Engine_Config",
+        "cost": "-4",
+        "entry_cost": "0",
+        "category": "ORBITAL",
+        "info": "",
+        "year": "1963",
+        "technology": "orbitalRocketry1963",
+        "ro": true,
+        "orphan": false,
+        "rp0_conf": true,
+        "spacecraft": "",
+        "engine_config": "AR2",
+        "upgrade": true,
+        "entry_cost_mods": "5000,PumpReignition,throttlingTP",
+        "identical_part_name": "",
+        "module_tags": [
+            "EngineLiquidTurbo"
+        ]
+    },
     {
         "name": "LR129-P-1",
         "title": "LR129-P-1",
@@ -14020,7 +14066,7 @@
         "spacecraft": "",
         "engine_config": "RL10",
         "upgrade": false,
-        "entry_cost_mods": "37549, HydroloxPumps",
+        "entry_cost_mods": "37549, HydroloxPumps, PumpReignition",
         "identical_part_name": "",
         "module_tags": []
     },
@@ -15619,7 +15665,7 @@
         "spacecraft": "",
         "engine_config": "S155",
         "upgrade": false,
-        "entry_cost_mods": "10000, Wasserfall",
+        "entry_cost_mods": "10000,Wasserfall,throttlingTP,PumpReignition",
         "identical_part_name": "",
         "module_tags": []
     },
@@ -19086,7 +19132,7 @@
         "spacecraft": "X-2",
         "engine_config": "XLR25",
         "upgrade": false,
-        "entry_cost_mods": "XLR11-RM-5, 5000",
+        "entry_cost_mods": "5000,XLR11-RM-5,throttlingTP,PumpReignition",
         "identical_part_name": "",
         "module_tags": []
     },
@@ -19136,6 +19182,29 @@
         "identical_part_name": "",
         "module_tags": []
     },
+    {
+        "name": "XLR42-NA-2",
+        "title": "XLR42-NA-2",
+        "description": "",
+        "mod": "Engine_Config",
+        "cost": "0",
+        "entry_cost": "0",
+        "category": "ORBITAL",
+        "info": "",
+        "year": "1957",
+        "technology": "orbitalRocketry1956",
+        "ro": true,
+        "orphan": false,
+        "rp0_conf": true,
+        "spacecraft": "",
+        "engine_config": "AR2",
+        "upgrade": false,
+        "entry_cost_mods": "10000",
+        "identical_part_name": "",
+        "module_tags": [
+            "EngineLiquidPF"
+        ]
+    },
     {
         "name": "XLR43-NA-1",
         "title": "XLR43-NA-1",
@@ -19330,7 +19399,7 @@
         "spacecraft": "X-15",
         "engine_config": "XLR99",
         "upgrade": false,
-        "entry_cost_mods": "50000, XLR11-RM-3",
+        "entry_cost_mods": "50000, XLR11-RM-3,throttlingTP,PumpReignition",
         "identical_part_name": "",
         "module_tags": []
     },
@@ -19339,7 +19408,7 @@
         "title": "XLR99-RM-2A",
         "description": "",
         "mod": "Engine_Config",
-        "cost": 50,
+        "cost": 10,
         "entry_cost": 0,
         "category": "ORBITAL",
         "info": "ROEE",
@@ -19351,11 +19420,32 @@
         "rp0_conf": true,
         "spacecraft": "",
         "engine_config": "XLR99",
-        "upgrade": false,
+        "upgrade": true,
         "entry_cost_mods": "5000,XLR99-RM-2",
         "identical_part_name": "",
         "module_tags": []
     },
+    {
+        "name": "XLR99-RM-3",
+        "title": "XLR99-RM-3",
+        "description": "",
+        "mod": "Engine_Config",
+        "cost": 27,
+        "entry_cost": "0",
+        "category": "ORBITAL",
+        "info": "",
+        "year": "1966",
+        "technology": "orbitalRocketry1966",
+        "ro": true,
+        "orphan": false,
+        "rp0_conf": true,
+        "spacecraft": "",
+        "engine_config": "XLR99",
+        "upgrade": true,
+        "entry_cost_mods": "50000,XLR99-RM-2A",
+        "identical_part_name": "",
+        "module_tags": []
+    },
     {
         "name": "XM-20",
         "title": "XM-20",
diff --git a/Source/Tech Tree/Parts Browser/data/ROEngines.json b/Source/Tech Tree/Parts Browser/data/ROEngines.json
index 6998e87290..6692e437b7 100644
--- a/Source/Tech Tree/Parts Browser/data/ROEngines.json	
+++ b/Source/Tech Tree/Parts Browser/data/ROEngines.json	
@@ -8226,7 +8226,7 @@
         "title": "XLR99",
         "description": "",
         "mod": "ROEngines",
-        "cost": 315,
+        "cost": 333,
         "entry_cost": 0,
         "category": "ORBITAL",
         "info": "Engine",
diff --git a/Source/Tech Tree/Parts Browser/data/ROEnginesExtended.json b/Source/Tech Tree/Parts Browser/data/ROEnginesExtended.json
index e8a820dace..f824e7d6f9 100644
--- a/Source/Tech Tree/Parts Browser/data/ROEnginesExtended.json	
+++ b/Source/Tech Tree/Parts Browser/data/ROEnginesExtended.json	
@@ -1,4 +1,28 @@
 [
+    {
+        "name": "ROE-AR2",
+        "title": "AR-1/2",
+        "description": "",
+        "mod": "ROEnginesExtended",
+        "cost": "91",
+        "entry_cost": "0",
+        "category": "ORBITAL",
+        "info": "",
+        "year": "1957",
+        "technology": "orbitalRocketry1956",
+        "era": "",
+        "ro": true,
+        "orphan": false,
+        "rp0_conf": true,
+        "spacecraft": "",
+        "engine_config": "AR2",
+        "upgrade": false,
+        "entry_cost_mods": "XLR42-NA-2",
+        "identical_part_name": "",
+        "module_tags": [
+            "EngineLiquidTurbo"
+        ]
+    },
     {
         "name": "ROEE-AJ1200",
         "title": "AJ1200",
@@ -1406,7 +1430,7 @@
         "title": "XLR99-RM-2A",
         "description": "",
         "mod": "ROEnginesExtended",
-        "cost": 315,
+        "cost": 333,
         "entry_cost": 0,
         "category": "ORBITAL",
         "info": "",
diff --git a/Source/Tech Tree/Parts Browser/data/Stock__RO_Config.json b/Source/Tech Tree/Parts Browser/data/Stock__RO_Config.json
index 1997b98121..17f186467d 100644
--- a/Source/Tech Tree/Parts Browser/data/Stock__RO_Config.json	
+++ b/Source/Tech Tree/Parts Browser/data/Stock__RO_Config.json	
@@ -2300,7 +2300,7 @@
         "title": "XLR99 Spaceplane Engine",
         "description": "LOX/Ammonia gas generator engine which powered the X-15 spaceplane. The first large, throttleable, restartable liquid fuel rocket engine. Diameter: [1.42 m]. Plume configured by RealPlume.",
         "mod": "Stock (RO Config)",
-        "cost": 315,
+        "cost": 333,
         "entry_cost": 0,
         "category": "ORBITAL",
         "info": "Engine",