I sprayed mine black too. I've got a pic but It's too dark and too bad of a camera to really see. but I post it up anyway.
Regular spray paint man. You just gotta do it professional. You gotta put your finger lightly on the sprayer of the can and get it coming out steady but light. Then keep moving over all of the rim kinda fast and make sure not to go over the areas again that look done.
I really was surprised at how well they come out. Professional work it looks like for real. but don't wsah them hard I'll tell you that. Paint will start to come off not completely but you'll see what I mean if you wash them to hard by hand...
anyway heres the pic