I recommend Nokian Hakkapelittas. Funny name awesome snow tires. The company is in Scandanavia and they do testing on a snow/ice covered track.
The skinnier your tire the better it is for winter because you want the tire to bite through the snow not float on top. I recommend going as skinny as you can. I have 195/55x15" Hakkapelitta 2s on my OEM Si wheels. I think they came out with a newer and better tire the "RSI". My 2s are also studdable.
http://www.nokiantires.com/newsite/tires.cfm
the 2s
the RSI
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