Got a G35 coupe w/brembo brakes dropped with Tein S-Tech, Notice everyone mostly runs 20's but no width listed. What is a good setup. I'm thinking 20x8.5 front, 20x10 rear. I really want to run 20x10.5 rear. Would there be much difference ?

 

You can run 20x9.5 front +18 to +22 offset with 245/35 tires and be fairly flush. You can run 20x10.5 rear with same offset with 285/30 tires and also be safe.

After exhaustive research, that's the setup I'd go with.