Can't speculate on stock tires and snow, only had my BFG AT KOs on snow. If anything, the 15" wheels give you more tire size choices (as you noted) and the tires themselves will be quite a bit cheaper for the same effective diameter. I'm sure the 265/70R16 (30.5x10.5 tire) is much cheaper than the 265/65R17 (also a 30.5x10.5 tire) and we know the 15" are cheaper still. It will take you a few sets of tires to see the savings though if you have to cough for new wheels in the first place.
Brent
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