Seems like 17x9 is common wheel people use on track. Is this preferred size for this car? What about offset?
I have 17x7 right now but reading threads it looks like not wide enough for track tires.

 

If you don't want to hassle with fender rolling then 17X9 62-63

If you do want to mess with fenders then I would go with 17X9.5 48 or the 949 17X10's

 

Rolling fenders is no problem, done it before.
More interested what would be ideal rim/tire size for road race tracks.

 

I run 17x10 +72 I think
whatever 949 sells in the 17x10 size

you will have to run spacer in the front but the rears fit....ish.....
I get slight rubbing in turns like 6 at laguna where it compresses the suspension allot.
Also I run 275's but if your NA 255 may be enough and a 17x9+63