35,000 on my '99 coupe's GY EMTs
I researched the usual brands including Firestone, GY, Michelin, Pirelli, and some Korean. I am very pleased with my purchase of Michelin Pilot Sport ZPs all around. There is no reason for me to give up the run flat feature. This '99 is my daily driver in all weather conditions.
The Michelins provide a more solid feel when cornering and changing lanes... even at lower speeds, more control at highway speeds, and are less noisy that the GY EMTs. The Michelins take pot holes and big bumps at both low and high speeds by rolling over them, instead of hitting them head on with a jarring feedback. The Michelins are definitely much better in snow and wet conditions. If I were to buy a C5, I would transfer the Michelins to the new car and leave the GYs for someone else.
Peter