Create a second rFactor installation just for testing. Drop your extra car mod there. If it crashes vanilla rFactor, it will never work in RI.
Important: Most Race 07 mods work with Race Injection if placed correctly. race injection 12110 mods extra cars re install
You want more cars. You find a brilliant 2023 F1 mod or a GT3 pack. You drag the Serie folder into rFactor/GameData/Vehicles. You launch the game... Crash. Create a second rFactor installation just for testing
Here is the technical reality of Race Injection 12110: race injection 12110 mods extra cars re install