Guys I need some help trying to find out if a set of wheels would fit my 2008 AT G37s coupe as I'm trying to order the tires?

I got a set of rims that are:
Front 255/40R20
Rear 285/35R20

Thanks.

 

Those are tire specs, width in millimeters/sidewall thickness, and diameter.

Wheels will have the diameter in inches, the width in inches, and the offset.

Try again.

 

For those tires you listed you'll need rims for the front 20x8.5 or 20x9" w/ an offset about +30 to +35
For those rear tires I'd try a 20x10 +35
You also need to make sure whatever wheels you choose that they'll clear the big front brake calipers.
Here's a template that you can send to your wheel vendor to check clearance
http://www.conceptzperformance.com/i...akeoutline.pdf