i dont really know too much about winter tires but i know that as long as you have a lot of nice deep tread then thats the best. i would go with blizzaks because their mainly top rated for snow and icey conditions.
Is it lowered at all? Going up a profile size could give you problems when it comes to turning, or if you hit a big enough bump, you could rub your fenders. Do you have after market rims? Using stock gts rims I'm guessing? If you're getting another set of rims, go with 15's, that way you can get 195 or 205/60 15's, a lot cheaper. Got toyos for 100us each, installed. And the tread on them is crazy!