Potts, are they chips on the wheel or is it whiteworm? They won't replace them under warranty if they're chips.
As far as the piano black paint on the wheels is concerned, mine are still almost as new after 25 months [admittedly only 8k miles]
I don't know how you've managed to lose the paint; do you clean them with a brillo pad?

You should regularly wash them carefully with car shampoo [Not with spray-on wheel cleaners] and wax them at least once a month.