Ok, well back when I was stock I could run in the 15.7's and I even dropped down to 15.6 once. Since my car was stock I have lowered it, added a CAI, and got some 17" ADR GT-Sports, with Michelin Pilot Sport Z rated tires. Before I just had my stock wheels with the stock Michelin Pilot XGT-V4's. My new wheels shouldn't really be a factor cause they aren't to heavy (like 19-20lbs probably). Could someone please help?