I haven't seen any report on this combo yet, but have seen some people with an interest, so here's my experience: I've got the stock muffler uncorked, YZ cam timing, throttle stop removed, and airbox lid removed. First, the quality of the power bomb looks good. The welds around the bulge look fairly clean, and the fit is just right. The only problem I had installing was I had to remove the stock muffler to get it slipped over the Power Bomb. For testing, I was out in the Arizona desert with density altitude about 4500 feet and high humidity. I hadn't ridden in two weeks, so some comparisons may not be accurate. I richened up the pilot screw about 1/8th turn from before which wasn't enough as I still had some minor popping on deceleration. As far as noise goes, I didn't notice the bike being any quieter. Power-wise, I didn't notice any increase in power, but there definitely wasn't any decrease throughout the range. As far as I can tell, the biggest advantage of the Power Bomb will come when I need to change oil next. No more need to pull the stock header up and out of the way anymore!!!