HI Deacon,

I suppose in a restrictive exhaust system, drilling an additional hole or enlarging the existing hole would help but it appears that the stock muffler is adequate in terms of flow (of course assuming the baffle is cut per Dax instructions).

I believe Red did a test of the new High performance muffler from Dax and did not find any performance increases (the new muffler had a larger diameter header and exhaust opening).

A properly designed/made tuned exhaust/expansion chamber is the exhaust of choice when looking for performance increases.

Andrew