It wasn't really a test, it was more of a driving comparison. They don't list the 1/4 mile trap speeds.
There were three drivers: Executive Editor Mark Gillies, Technical Editor Don Sherman, Assistant Editor Rusty Blackwell.
Everyone loves the GT, because it feels and looks so special. Sherman would take it, because "it is the most collectible, the most exotic, and I would keep it for the rest of my life as a valuable heirloom to pass on. Plus it's great to drive."
Blackwell would take the Z06: "If I could afford a car like this, I would want to drive it a lot. It's such a stealth car, you could stay under the radar with it, it's easy top drive day to day, but it's nearly as quick as the GT."
Me? (Gillies) I love all three. Were money no object, it would be the GT. But for most of us, money is an object. Someone like me could afford a Z06 as a toy for track days and for blasting through the countryside.