I've ridden a few times with it now, and quite like it. My bike hasn't hot-stalled in a corner since I've installed it, and the throttle response on the track is much better. Crack the throttle = instant response. It hasn't bogged on a hard landing either. If you install one of these, be sure to remember that you've introduced air into the accel pump system, and it will take a lap to two (and some throttle twisting) to work it out. DON'T JUMP ANYTHING! Once all the air is bled, away you go. One other thing - my bike still doesn't rev like a 2-smoke when I crack the throttle on the stand. It will still cough. Personally, I don't care because it is the on-track performance that matters, and I haven't been able to make it cough on the track. Boyesen does recommend a richer fuel screw setting which I will experiment more with. Verdict: Good stuff. Worth the $$ IMHO.