A 18x10.5 square setup seems to be popular for track use. Just needs a spacer on the rear wheels.
Maybe try searching also. This question has been answered many times on the forum already.
__________________
2011 370Z 6MT Sport Gun Metallic | ARC | CJM | Ecutek | FI | Fujimura | R2C | SPL | Stillen | TWM | Z1 | ZSpeed | |