Be very careful buying nonstock wheels. And that includes aftermarket copies of GM original equipment wheels.
Most tire shops cannot remove and replace a run flat tire on a non stock wheel. None will guarantee you they will not damage the wheel or tire. Many nonstock wheels will not accept the tire pressure sensors (there can be problems on the inside and/or the outside). None will guarantee you they won't damage the tire pressure sensors when taking off or putting on a tire.
Many chrome non-stock wheels are steel and are much heavier than stock wheels, and they can pick up a magnetic field that screws up the tire pressure monitors.
I run non-stock wheels made especially for the C5 by Cray, a well known and well-respected company and I still have had many problems. Just recently I had to replace a whole set of tires because I had a flat, my tire pressure sensors went crazy and the shop ruined the run flats taking them off. I replaced the run flats with regular tires this time.
I wouldn't buy another set of non-OEM wheels unless I found a shop that could assurre me they had mounted and fixed flats with the wheels under consideration, especially so if you want run flats.
I have Cray Scorpions in Chrome with Michelin Pilot Sport A/S tires.