I have 4 continental all seasons. Live in the Philadelphia area and I will be using my crossfire during the winter. I may be fine with the AS's so I will wait to see how it handles, but I was considering getting two more 18 inch wheels and snows.

Does anyone have thoughts on this, what size size tires would be recommended to use and is there any risk of damage to the car? Tire guy told me not to switch wheel sizes, but I believe the manual suggests 4 18s with snows all the way around. Please note, I plan on leaving the all weathers on the front as I am sure they will be quite sufficient for steering and braking.

Would like to know what others do for winter driving.