On my C6 Z06 I run 10.5 X 18 Forgelines front with Pilot Sport PS2 315-30 ZR18 (N4 Porsche) OEM rear tire for GT3 and 12.5 X 19 Forgelines rear with 345/30ZR19 C1 Dodge Viper, OEM ACR Tire. All 220 UTQG.
When new, incredible grip for street tire, first event, it launched so well that I almost blew by the first autocross gate because I was expecting massive wheel spin and it hooked. Downside, razor edge breakaway transition in cornering; I'm not good enough to drive it to its potential, particularly as it heatcycles out. A6 is so much easier and forgiving to drive in comparison.
Danny Popp won 2012 ultimate street car challenge with C6 Z06 on this same combo and was still running them last spring when I saw him at a ProTouring type event at the Autobahn. He was blowing those guys away.
Talk to Luke at Tire Rack about them. Another Downside, very expensive, but they have worn much better than Luke suggested, but no longer have competitive grip, but still good tire for street.