Theres a Shop Already in the game for tunes it thinks its called custom gearboxs and there is a performance parts store

Community Cars Body Shop is for mods you either downloaded from Workshop or manually installed. It's just the parts store for those car mods. @Carl-TurtleonYT pointed you to the other stores for special parts... basically the high performance engine parts and gearboxes. If you were meaning something else different... like modding the car to have different parts when finding them in salon, auction, barns, junkyard... that's done by editing the bodyconfig.txt file for the cars.

Originally posted by Carl-TurtleonYT:

Theres a Shop Already in the game for tunes it thinks its called custom gearboxs and there is a performance parts store

ik thers is a performance parts shop but after installing mods it seems to have been replaced by siad mod car body shop

No, the community body shop is a different shop. There is also a performance / custom body parts shop for game's default cars. It will have things like custom bumpers, lights, and hoods.