My silver BBSs had been macked a little by previous owner, so I chose to do gloss black cuz they add an extra layer of clear coat which soaks/fills the little groves from the "mackage". It did not cost much, $150 for all four rims. Make sure they know they are not steel....very important when it comes to the baking. Post some pics when you get it done.
Personally it was one of the best things I have done to the car, gives it a sick tuner look and helps hide brake dust.