I want to get into a set of Nitto NT555R's. Specifically, 305/40-18's rather than 305/45-18's. The OD is almost perfect. But the Nitto site says the minimum width of the rim starts at 10", not 9.5".
I ran those for a couple of years with no issues as far as rubbing - but even aired down to 25psi they wore in the middle rather quickly due to rim width. On a related note, be aware that all the national tire chains (NTB, Discount, etc) cracked down this year on installing tires on rims that are less than the recommended width. Specifically, they will not install a 305 on factory rims under any circumstances, even if you claim they are for weekend track duty. I just went through this recently, and had to go with 285's. I'm sure if I'd taken the time to find an independent tire shop, I could have had 305's installed. But the premature wear problem prompted me to try the 285's for a change.