I went with 136x1.25 Ripsaw on my ZR800. I have no need for studs as I ride the trails and fresh powder, no ice racing for me. I was also leaning towards 8" wheels, but even my dealer said the "bang for the buck factor" just isn't there. There are a lot of other things I could do for $300-400 and get more performance. I guess if a guy is racing every week for title/money, they may help. But I don't think I would see a great advantage to having them.