I have the 4th gen rear and was wanting to get 17 x 9.5 zr1 wheels.
Is there a big difference in using the 38 mm offset compared to the 56mm.
Anyone using the 56 mm got some pros or cons and anyone using the 38 or 36.5 mm got anything?

 

Whoops, NM, didn't see the part about you having a 4th gen rear.

FWIW: I have 17x9.5 +56mm ZR1s on my 4th gen rear. I would think you would need a 18mm spacer, thats about 0.07" for 38mm BS, or a 3/4" spacer for the 36.5mm BS.

 

i dont want to use adapters on the front for racing purposes so whats the max size wheel and tire for the front? without spacers.
Could i use the billet adapters while racing?

 

Unless you get the special ZR1s made for 3rd gens, you will have to run a spacer up front. I run a 2 1/4" spacer up front in order to clear the tie rods.