For what it's worth, Laura's presently shod with Dunlop Direzza DZ101s in 215/50-16. Even given the stock size, I expect these tires to be half-assed in the snow. The size of your tires is playing a part, yes, but it's the style of tire, too. Unless you want to run an all-season, you may be stuck doing the snow tire hokey pokey every winter and spring.
If you're most concerned with the tire size at this point, a return to the stock specs is probably your best bet. If you end up running snows, you could get away with 205/55-16.