I'm wanting some 16" and what I'm needing to know is what are the premiers of the offset must me in?

 

16x what? It's all about the width of the wheel to determine the correct offset. I'm running 17x8 in the front and 17x9 in the rear. Had to go with a +35 offset on the rear to fit that meat.

 

I will probably go with a 16x7. What offset do you have on the front? The rims a want have a 0 or 38 offset And no in between sizes. So will a 16x7 with a 0 or 38 offset work?

 

Stock wheel information:

84-85 all(except AE): 15x6.5 +30mm
86 non-turbo: 15x6.5 +10mm
84AE + 86 turbo: 16x7.0 +20mm
87-89 non-turbo: 15x6.5 +20mm
87-89 Turbo: 16x7.0 +30mm

This is the factory wheel info, visit this site to check the offset parameters
ZBUM's Nissan Z31 300ZX Wheel and Tire Limits

You Need to add your car to your SIG so we know what you drive.
Im running a 17x8 +25 on the front. dependining on what car you have... probely need a +20 to 30 for a 7" wide wheel