It's not 1985 anymore. You won't ruin your car by driving it in the winter due to salt on the roads; modern cars will not rust away. I have had my car 8 years, including some nasty winters, and there's not a speck of rust anywhere.
I have AWD with all seasons, but have read plenty of posts by RWD owners that use winter tires. Some say that's a better setup than AWD with all seasons. Unfortunately, I can't help you on sizing. Good help on tirerack.com though.