I went with 20x10.5 Forgestars and Michelin Pilot Super Sports. That's 30% wider on the front than stock. But the Michelins I got are also short, so they lower the car more. See:
http://www.camaro5.com/forums/showthread.php?t=207261
Great setup. I really like. Grips like hell. My friend who is an instructor has a Corvette and switched his tires to Super Sports because he couldn't get his car to grip in corners like mine! True story.
But I am really low now. Have not measured lately but I no longer go over speed bumps - if there is one, I back out. I put Dynatech headers on and they have a flange around the point where the cats connect to the headers, and it is LOW LOW LOW. Just changed my driving habits is all. Newly built parking garages have these rubber expansion joints that are set in raised hump-like things once on each level - gotta go over those at an angle, but it works. At first it pissed me off but once you're used to keeping an eye out, it's not tha tbad.