Switching up the style of car a bit, since the process isn't limited by factors like undercuts it might be fun to print the twisting form of a neon sign, at this scale the lettering would be just 1mm thick!
Rollllll up one and all! Grand opening of Coolhand Motors coming soon, and boy do we have some bargains for you! Low miles, all previous owners were genetically modified elderly ladies...
That C4 is stunning, maybe just needs a couple of tweaks in the door handle inset (softer edges?) and the panel line is just a little off/inconsistent but you probably already noticed it.