yeah i have a friend who has been riding for probly 30 years. he is very religious about tinkering with his machines and knows his stuff and does his research. he runs it. to me thats saying something.
i have one on my 05 800, no problems and it sounds really good. It is the "quiet" thing and its plenty loud, more so than a trail or standard MBRP, hope it helps, also like the way it mounts, stays in place.
I recently bought a used 07 m8 and it has the thing on it. Its pretty loud. Can't really comment on performance because I haven't put the stock can on to compare.
I will complain about the way it mounts though. It really hangs a lot of weight off the end of the pipe and the springs at the y-pipe really have to work hard. My donut has started puking oil and one of the springs actually popped off and scored up the clutches. I added some springs to help stabilize the exhaust but am still seriously considering ditching "the thing". The MBRP can mounts way nicer.