I'm now running 4 rears. Traded with a G37 sedan owner my 2 front wheels for his 2 rears. Now running 20x10.5 et25 all around with a 20mm spacer in the rear.
*Only took the Z out to get the front tires/sensors swapped over and took a quick photo. Washed and waxed the car and now it will go into hibernation before spring.*