Heres my thread on the subject. Ive already used mine. Not sure where your from but plowed roads in PA are still snow covered. They not only help you go on snow and ice, the also help you maintain control and stop. They may not be a must but ive spun a car around on just 2 front snow tires... Not fun. Get all 4. Plus i recommend you get a set of winter wheels too. Not only will it save wear and tear on your nice set from switching the tires and road rash, they will also pay for themselves in the long run. You dont have to pay the tire shop to swap your tires twice a year and you can swap them yourself so no waiting for them to do it. Your summer tires will also last longer because your storing them 3 months out of the year. Tire width inst a big concern on a small car like ours. If you where off roading in a 4wd rig then maybe. Dont be too concerned about it. Ground clearance will get the focus before worrying about the tires sinking or riding on top the snow. Im running stock size 215/55/16's on stock focus steel wheels which already had tpms installed on them.
Winter Tires.....Heck Yeah