Has anyone used a 225-45-18 tire for snows on their S5? I like that the tire is slightly narrower which should lead to better traction. Going up and down the hills of Pittsburgh in the winter in the middle of the night before salting or plowing (as necessitated by my job) can get treacherous, and I am looking for any advantages I can get. I am interested in anyone's experience with this. Sorry if this has been touched on in past threads, but a rather lengthy search pulled up lots of snow tire comments, and + sizing questions, but not so much in the way of down sizing. Thanks.