So I had Ikon GT5 rims 17" with 40 series Yokohama Avids, and I slapped the stockers back on with Kumho Ecsta rubber on them (50 series). The ride difference is amazing. I don't know what to do now. I think I actually prefer the look of the stock wheels, and with the Eibach springs it doesn't much matter since overall wheel diameter is almost exactly the same. Any of you guys run 40s and then switch back because of the bumpiness? I may put one side stock and one side with the Ikons and get some thoughts with digital pics.