I am not a fan of powdercoated wheels, I have seen a few posts on the track forums regarding some powdercoated wheels breaking under track temps and apparently it was all down too the baketemperatures affecting the wheels (bot sure how true this is tbh but I just painted my own, they are not perfect but it was my first time ever painting anything so I will more than likely look to do them again when I have more time and facilities to do it as they were done in my garden...
TGM sport paint wheels, I think if you go to a bodyshop they'd be able to quote for it.