I was toying around and looking at possibly getting some 18's on the SE. I was using a tire size converting application to find out what size tire I should get if I got some 18's. Below is a screen shot of the results
As you can see in the results, a 235/45R18 matches best with the overall diameter of the stock tire. Selecting that tire, the next screen (not shown) shows the variance of OD is 0.1%... quite impressive. Width goes from 8.5 to 9.3 inches.
Does anyone have any testimonials? I see a lot of you have gone with the 245/40 18