My main concern right now is snow tires. I cannot find good science behind what size snow tire to get. Skinny tires should plow through snow easier but, wider tires provide more surface contact on ice.
So, put 18" winters on the stock wheels (not as expensive) or buy 17" wheel and tire set (expensive)? Any advice on this would be appreciated, even links to good science.
If you go with your stock size you should be fine. I ran 225/45/17's on my SRT-4 and my STI. They were the blizzak ws-50's these are the best snow tire in my opinion, but they aren't speed rated. I still have them and they're for sale cheap.