locate your steam folder steam apps workshop content in that file is files just look for the mods there

still cant find it :(

By default, they are kept in the \Workshop\Content\ folder. Each game has a specific number associated with it for Workshop. Once you've Subscribed a mod for a game from the Workshop, Steam creates that games numbered folder in there. Then each subscribed mod has a number associated with it. So, each mod you subscribe is in a numbered folder under the games numbered folder. For this game, the default location is;
C:\Program Files(x86)\Steam\steamapps\workshop\content\645630\

Each mod from Workshop is in a numbered folder under that \645630\ folder. Look inside a numbered folder and look at the 'Name.txt' file to figure out which car it is. If you're not finding the car in question, try unsubscribing the mod from Workshop, restart steam, Subscribe the mod again, launch game and, check 'ShowRoom' from main menu and see if the car is showing up. If not, it didn't install correctly for some reason.