Car paints are great if you're doing solid colours - I've got several guitars I did 15-20 years ago and the finishes have held up really well. I wouldn't bother with metallics though, unless you're a very skilled sprayer, because you can't really wet-sand between coats.
But if you're going to use spray cans make sure it's in a very well ventilated area that's easy to clean!
You get loads of little paint particles in the air which settle as dust. A long, long time ago I spray-painted a couple of guitars in my parents' kitchen, and when I'd finished (20-odd coats later) there was a fine layer of blue dust everywhere, even inside the cupboards.