finally decided on 18s for the track
 

Found a sweet deal on a set of 4 18x8.5" Rays Track 350Z wheels. Going to send them to weldcraft and have them widened to 9" front and 10" rear and be done with it! Would go a little wider, but since they add to the back side, the above sizes seem to be optimal, plus they will be wide enough.

how are the offsets on those? I'm assuming they are the 6-spoke with the dimples in each spoke?

Yes, they are the 6 spoke Rays with dimples. I'm getting a set of 4 rear wheels, all 8.5 +33, when I get them modified, they will all be 9.5 +46. The fronts will have 5mm less inner clearance and stick out 8mm farther than stock, and the rears will need my 20mm spacer, and with the spacer have 2mm less inner clearance and stick out 2mm less, if that makes sense.

I plan on running 275s all the way around to dial out some understeer. It was a great setup on my 350Z.