300ZX Twin Turbo came with 16x7.5 fronts and 16x8.5 rears. N/A cars came with the 16x7.5's only. Here is a couple pictures of my car with the TT rims.
Probably doesnt help you much though...
edit:
Offsets are: 16x7.5 +45, 16x8.5 +35
I'm currently fitting a 17x8.5 +30 on my S13 now, so if anything you should be good with a 5mm slip on spacer.