I have a set of stock silver (non polished) wheels that I had polished at a shop. They are tough to keep clean and it was $150 per wheel to have it done. It makes more sense to just buy different wheels if you want a different look. That is my opinion though.
On second thought it depends on your budget. $600 will probably get you the wheels the way you want them but it won't buy you a nice set of aftermarket wheels. If you think about it though I could have bought another set of wheels that were factory polished for the price I paid to have my original wheels polished! Ironically only a few months ago I went and bought another set of stock wheels for beater/winter use. So think ahead.