I posted the same query over on B-bodies only earlier this week. Got pretty much the same answers. I shot mine with the Testors paint and it was fine for a while but has faded to almost white. So I'd like to do it in a higher quality 2-stage paint. There are spray bombs out there, here's a link to one: Price is reasonable enough but its still only a spray bomb - no catalyst and no hardener.

http://www.mrmoparts.net/products/paint-purple-for-horn-68-72-plymouth-roadrunner.html