lol, you have a friend that used spray paint when you have a powdercoating business? I hope it was before you started doing powdercoating
Also, dupli-color makes a wheel specific paint that I have heard is pretty good. I personally refinished some 2004 350z wheels with the gun-metal color to sell them and they turned out pretty good for a spray-can job. I dunno if I would use that on my Rays wheels, but for your 18's I wouldn't be as scared.