Are you trying to (like new colors) or add a new car ?
It is listed in GTA V's DLC list as a major content addition. 2. How to Use mpchristmas3 Mods (Installation) mpchristmas3.rar
If you can tell me what you want to do with the file, I can give you the exact steps. Updated Spawn Colors For Los Santos Drug Wars Vehicles 1.0 Are you trying to (like new colors) or add a new car
Contains models for the Railgun XM3 (WEAPON_RAILGUNXM3). How to Use mpchristmas3 Mods (Installation) If you
Includes the 300R, Boor, Broadway, Entity MT, Eudora, Hotring Everon, Issi Rally, Panthere, Powersurge, Tahoma, Tulip M-100, Virtue, Brickade 6x6, Cargo Plane, Journey II, Manchez Scout C, and Surfer Custom.
If you downloaded a .rar file (like the "Updated Spawn Colors" mod), it typically includes a carvariations.meta file meant to modify the vanilla cars. Extract the .rar file using 7-Zip or WinRAR. OpenIV: Open OpenIV and ensure "Edit Mode" is active.