Ive always had a set of summer & winter setups for both my contours. However if you are too late to take off or too early to put on the wrong setup you could end up in a ditch like I did!
When I originally bought my car I had the 14's with whatever stock tires were on it and I once almost lost control on a large pach of ice on the freeway and since then have had the winter tires which I really enjoy.
