It is quite loud, but no more than an Akro or Arrow system that some have on their KTM's. It is slightly louder than standard
It is stamped as road legal, and when "going easy" is quiet (do the twin outlets make a difference?)-but not so when giving it the berries (sounds nice in London's Limehouse Link). Power definately comes in with more of a kick now.
One other important benefit is that I seem to be getting more miles out of a tank of petrol, on the same run at the same speed. Maybe the weight loss (not mine, I hasten to add) and the easier breathing motor helps.
Still had no time to change to the short rear guard, let alone move the indicators.