I am running 19x8.5" wheels with 265-50-19 Pirelli Scorpion Ice and Snow tires. They work very well and look pretty good on the car. I thought about 18's but they look a bit out of place with the "is" bodywork. I think running 20x8.5 all around with 265 or 275 is a good solution too. 255 might also work, but I felt 255 would not fit a 8.5" rim as well as a 265 does.
