The black zr1 wheels you are refering to were actually only offered on the '96 Corvette Grand Sport. (blue car white stripes, two red hash marks on the one fender, only 1,000 cars made).
I have a set on my '93 anniversary edition, but I chromed them.
I too would like to see these on a GN!
FYI, front wheels are 9.5 x 17 (275-40ZR17)
Rears are 11 x 17 (315-35ZR17)
If you had a '96 convertable, it had 9.5x17's on all 4 corners.
