Great info from all, but since you didn't mention where you are from, it may be important to purchase, depending on whether you are in a dry clime or a wet one. If you are in a dry area, call Luke at the Tire Rack and get the MXX3's ( 285's actually give you better steering response than the 275's, and I would order them regardless of the tire selected ), since they are priced very,very, low. If , on the other hand you are in a rainy area, spend the money on the Sports, as the MXX3's are lousy in the rain.
PS - If you plan on doing track time, the only option is to go with the MXX3's - call Luke.