You might look at the speed rating when deciding how you want your car to ride. The lower it is, the nicer the ride. RS3's and Star Specs ride like an A6 which you can drive on with NO air in. The stiff sidewall is great for handling but not so great for a nice Sunday afternoon cruise with your sweetie. Width is only one of the factors on hitting in the front, height is the another. A shorter tire with more width will not be as likely to hit. Keeping the tire all the way inboard (offset) will also help to not hit the valance. It has been my experience that lowering springs usually bottom out unless you do something to prevent it. Shortening the struts is a good way to stop that. Hope that helps with your decision and doesn't just confuse you more. Sometimes I think my head will explode with all the decisions about how I want my Z. Good Luck, logr