Hello guys !
After checking on many modding websites, I don't found an answer to my problem :/
So I explain it here and maybe someone could help me.
I added some police cars with a mod called "Added Police Car Slots". I added files to the game, like I do for every mods, added theses cars to carvariation and vehicles.meta so for me, all is ok. But IG, when I spawn the car, the model is correct but textures are really weirds ... Looks like it don't use the right file. For exemple on a CVPI I added, the texture used for the livrery is the texture from wheels template ... So the car texture is pink, and glitched as hell... And it's the same problem with all cars I added. Where can be the problem?
I was thinking about post my carvariations.meta and vehicles.meta but I don't thinks it can really helps since I downloaded many cars from many sites .. But if you want it, ask me !
Here a screenshot. I added 8 others vehicles, but it's the same bugs so I just show 3 https://gyazo.com/9fcafb8980d9543fbec1630ec8b7def1