I have used future on car bodies as well. The stuff is really thin so you'll need at least a good 10+coats before u can polish/sand it to a brilliant shine..
I airbrush mine. It's a cheap alternative to lacquer clear coats, but like daggerlee says, u can put like 3 coats of lacquer clear on and your set..
on the plus side, future is acrylic (less harmful), smells better than lacquer too!