I now have this exhaust. I didn't perceive any change on power, acceleration, smoothness of the engine....nothing.
Decel pop is louder as Redrocket said but that is because the exhaust sound is louder, but it's the same intoxicating decel popping that the OEM exhaust albeit louder has and it's beautiful, it is music to my ears. Decel sounds like a WWII bomber.
I never want to remap or mess with the tuning because IMO the bike is just perfect as is, except for the ****ty sounding OEM exhaust.
Hope this helps.