Add-on cars tuning HELP

[NikkoHEHE]

On the server I am playing, the devs have a hard time figuring out why the cars can't be tuned. Tuned as in , tinting the windows , changing car parts etc etc.. Is there some script that is required or could it be something else? All ideas are greatly appreciated.

[Theoasterix]

Sometimes, tuning doesn't work due to tuning ID