Its a pretty old magazine, I remember the article as well. They even had a neat little map of the track they tested the cars on, where it showed all the braking and acceleration points of each car during each part, pretty cool.
The GTR just tore up both the Z06 and GT500 though, they didn't stand a chance. The GT500 seemed to fall behind in quite a few categories if I can recall correctly... Still wouldn't mind owning one, or any of those beasts.
Did the Z06 have the ZR1 performance package (forgot the exact name) on it? I heard that package will make the Z06 as quick as a ZR1 in cornering, etc?