Just got my 15/45 setup in 520 from AF1 onthe bike today. Talk about a bike on steroids! If you think you're bike's got a different personality with the 42 rear, you should see this. I can't race this thing yet, but I can do good wheelies and holly shite man, the bike wheelies so easily you could endo this bike really easily just pinnin it in first. I know Aaron uses this set up on his SBK (but he's a real racer), but wow, for a newbie track geek like me, it's going to take some getting use to. There'll be no pinning this bike in first out of any hairpins (maybe when I know how to handle it). Track day this Monday. Will let you know how it works out.