You should just powdercoat. Typical prep-work is sand blasting your wheels. In other words, they won't just powdercoat over your existing coat. This is the most cost effective way to get the finish you really want.
Thanks, everyone!
The current mileage is 17.6k. The black wheels do look better in person. They're "not so bad" after I see them in my driveway, and when I first saw it in the pictures my response was "gotta get the silver rims". Several mentioned that a wheel repair shop can fix this issue, but I am not so sure. I was told that they will do another powder coating over the black instead of restoring the OEM look. I am not sure I want another coat over them. I wonder if anyone here had the experience of restoring the OEM look. I'll call around and see. I also received many PMs both before and after getting the car. People try to convince me that there are people out there looking for black OEM with a good powder coating job, and I can trade or buy/sell for a silver set. I did see one set of OEM wheels in the FS section, but for the price I can almost get a set of nicer and more importantly, lighter wheels. I prefer to keep things stock, but a set of lighter wheels can benefit in so many dimensions. We'll see about that. I'll keep you folks posted.