How much did you pay per rim? Even with the $20/ rim powdercoating price it was a deal? Why not just prime and paint them? If you're gonna wheel them(and judging by the tire choice I'm guessing they'll see some dirt) then chances are that no matter what coating you use, you'll scratch them up either way. Two rattle cans full of Black gloss and one of black primer would only cost you like $10-20 to cover all three rims. All the items I even bought in powder coated form are scratched and rusting just as much as the painted stuff, other than my interior mods.