Originally Posted by Mal_B
Spot on. The headers are the major point of restriction in my opinion. There is also a large internal baffle in the Akrapovic muffler. Removing it also makes a substantial difference in both sound and performance. Doing both gave me about 1500 more rpm to play with.
For sure the baffle has to go to get the sweet sound. Very much like the Termignoni on the DUcati.