[Drivesthebeast]

As others mentioned above, tires (regardless if they are A/S or actual winter tires) that are smaller in width will absolutely work better for you in the snow. You do not want tires that bulge out enough from the rims that there is an obvious outward slant to the top of the tire (gets wider the further you go out away from the bead of the rim/wheel).

I proved this when I had my 78 Mercury Zephyr, and my dad's friend had a Ford Fairmont Futura several years ago. We both put 15" Mustang wheels on (mine were 15x7 Turbines, his 15x7 10-holes), and we both had similar aftermarket Mustang GT shocks and other parts. My car had 195 width tires, his had 215, and mine actually steered a lot faster, and had better handling reflexes to. That's because I didn't have sidewalls that were buckling/flexing while under load like his were.

I went with the 215/45 17's on the SVT wheels on the Focus, as these were the correct size compared to stock, according to the technical information available at the tire shop I bought them from (right from the Bridgestone/Fuzion/Firestone binders actually).