To add to the above, if you take the alloy back to bare metal, use etch primer before normal primer or it wont stick properly. It will still cost you probably £60 or more to do all 4 wheels properly. Various wet n dry, 400, 800, 1200 grade, 2 tins of etch primer, 3 (large) tins normal primer, 5/6tins base coat, 2/3 tins of lacquer. Also if your gonna do it properly if you have bad curbing, liquid metal.