you missed out on an awesome oppy. two weeks ago, there was a PERFECT set F.S. that were the correct offset on EBay, I think the final bid was $800. Thats a steal! Bigger wheels means thinner sidewalls but doesn't always make for better handleing. If the roads near you are pretty smooth and not many pot holes(never able to run 18's in NY)then the 18's will ride O.K., bad roads and stiff susp., you'll get jolted too much by the harsh ride. I personally thought they look too big on the 6 to the point that the car looks out of proportioned but T.E.H.O.!