As long as the overall height stays around 27-27.5" for the front and less than 28" for the rear, pretty much anything 295(maybe 305)mm or narrower will fit. Mine is lowered 1.75" front and 1.5" rear and the 255/45-18 and 295/45-18 fit fine with no rubbing. The 255/45 is identical to OEM height(27")and the 295/45 is 28.3" tall. I'm looking at a 29.2"x11.6" tire for the rear and I made a cardboard cutout and it looks like I will have room for that as well. As far as front clearance, you can run a 275/40-18 on a 10" wide wheel which is 26.7"x10.9"(tire/wheel size on the Roush Trak Pak Stang).