[gthal]

You should not drive on the summers in below freezing weather snow or no snow. Winter tires are a MUST HAVE if you are driving the car at all in winter. Summer tires are dangerous. There are examples on the forum here where people have thought they could get by without and ended up having accidents. If someone spends $60K or more on a sports oriented car, not spending $2,000 on a real winter set up doesn't make any sense at all IMO.

Whether you put winters on your 19s or buy 18s is personal preference. I ran a dedicated winter set up on 18s last year but this year put Blizzaks on the ZCP wheels. The 19s look better but they are less forgiving to pothole damage, etc.