I replaced my 20" Goodyears at 1,000 miles when I determined that I didn't want to get into an accident in the winter. I purchased the Conti DWS06s, and the difference in performance in snow, rain, and ice is like night and day. I believe the Contis have higher treadware (560) and speed (Y) ratings than the Goodyears. Having driven on the Contis since February I have nothing bad at all to say about them. I highly doubt you'll find a better all season replacement for this car, particularly living in an area where snow performance is necessary.
Also, I personally don't think you'll need snow tires living in Toronto. Where I live we get much more snow than Toronto, and the AWD system, coupled with the Contis, provided for solid handling in adverse weather. Of course, if you don't live in an urban or suburban area and instead live in the middle of nowhere where they don't plow frequently, then I would suggest winter tires!
And I'm sure now that I said all that I will get into a massive accident in the snow this winter.