Warning: This is a new resource working since SA-MP 0.3. It won't work in previous versions. it's seems not.
ÃÂÂÂctually, my friend, which was having his own server, scripted that the car will be tuned at the first spawn, but when it got destroyed, the tuning didn't appear. I think it seems that the tuning of the car will be everytime it respawns.