Driving through a couple inches of heavy snow in Boston last night, I definitely felt the RWD wheels slip frequently with the stock tires. Don't remember this much of an issue with my FWD Jetta that I was using Conti DWS06 with. Might have to suck it up and get snow tires.
Maybe it's my European upbringing speaking here, but how do you live in Boston and not buy winter tires? I live in Utah, I would terrified to drive without snow tires in the winter.