17's are fine in the snow! everyone thinks big rims = terrible in winter. The only reason I would say dont drive you're
MCS with ssr comps in the snow esp. around NYC is that the salt can def. effect you're rims (fading). I suggest you getting a NICE set of snow tires like Blizzaks or something of that matter. Why not just use you're stock rims with diesel snow tires?
Hope that helped a bit.
-Tyler