I have this pipe on my Derbi GP1. I chose it for two reasons, from what I've seen it is far and away better built for daily use than any of the pure racing pipes, being all stainless steel and titanium it doesn't corode at all and is very easy to clean to looking good as new with very little effort. Also it's got a bit more midrange than the pipes like the evo and mhr that I've ridden making it better for riding around town. I've got an evo 8 on order and will be dynoing it back to back with this pipe to see the exact difference. But I'll probably end up running the HM70 most of the time and just swapping in the evo when I want a little more top end, like next august when I'm going to take it up to the salt flats for speed week. Anyway, I've had this pipe for a few months and have been more than happy with it.