Powder coating rims
Most new rims are actually powder coated already (even polished rims typically are clear powder coated). Either way the rims need to be blasted prior to coating - the paint must be removed or the polished surface must be roughened up for the coating to adhere well. The only difference is a powder coated rim could cost 2X to blast over a painted or bare rim due to how resilient the powder coat is. Hope this helps...