I have rotar alloys on my be a3 I want have the edges re-done on all 4 wheels.......ive been told by a wheel place they can machine it and that's it,they be ok..........ive heard these need to be lacquered after being machined,but the chap whos sending wheels off to get done said,they don't need laquer,they be fine providing they washed with no harsh chemicals..............but ive been told if not lacquered after,they will corrode?