Originally Posted by thenorm
why not 15s. two responses promoting 16" with no posted reasons.
in terms of race tires, 15" is WAY more common so you have a great selection of tires of many widths to fit any budget.
essentially all 15" wheels will clear the brakes on a 2012. and the wheels and tires are lighter. so, win win in my books.
225/50R15 would be a good size for you and is quite common. It will just fit on a 15x7 wheel, although 7.5 or 8" would be prefered.
I don't know about way more 15 than 16. Forged 16 wheels are lighter than cast 15. The shorter tire is like a lower gear. You do need to wind the car out on the straights, tuck it in for the curves, and with the electronic management on the newer cars, the rotational speed of the smaller outside tire may interfere with the traction control. 16 also have a greater contact patch than a 15, giving more grip and braking. 225/50 seems like a lot of sidewall to me for a track tire.. More sidewall, more squirm. Less sidewall, stiffer.
Again, opinions are like tailholes, everybody has one. I have a Porsche 944 S2 that I do track, and use 16 instead of 18 due to price. If they were the same price, I'd go with the 18. No way would I step down to 15's.