well, i'm still running the stock map, but it feels by seat of the pants that the midrange is noticeably better. I'm leary of getting on the throttle much with my health problems right now, i have almost no feeling in my right hand.
as far as fitment and manufacturing, its first class, i'm use to putting on other exhausts that don't fit right or don't have great manufacturing, everything is perfect on the Akra, and that thing is way lighter than the stock muffler i took off, i would guess 10 pounds lighter or so...