For a fact, every car part is formed into a Autobot body. Not one piece of car left behind. But I will never understand where the seats of the car go. As we know, when Sideswipe made his first appearance in the second movie, he was a full Chevrolet Corvette Stingray, roof and all and he transformed perfectly. However, he his now a convertable Chevrolet Corvette Stingray, meaning no roof and yet he still transforms the same as the second movie mold. What do you think happened to his roof? Was the roof an important part of his body or was that probably an umimportant part of his body, like his Autobot appendix, Tonsils or one of his kidneys that he sacrifed? I mean Ratchet kept the same vehicle, just a new paint job. And Bumblebee is the same Camero, only with a new car tail. In any case I'll never understand how real life car forms into a robot body.