I have 18's on my 07 Limited from the 20" OEM wheels. The rubber is within .20" in total circumference between the two. The increased sidewall, in my opinion, makes the vehicle ride sooooo much better. As for fuel economy, I get no difference. As for looks, about the same, less flashy, which I like. I have 18" OEM wheels from an F150 from 2008, or so.