I was very fortunate to purchase an almost new Bursch muffler from a fellow 914World member. Next to my Mahle wheels, it is the best upgrade I have done to my teener. I just love the sound! Every time I go into town, people turn their heads.
I don't have a Gopro but I do have a very good professional grade video camera that has an awesome microphone. I placed the camera in the rear trunk and recorded my Bursch while accelerating. The microphone is less than two feet from the Bursch. Turn up your volume and enjoy.
http://www.youtube.com/watch?v=dRySuVF6jiw...eature=youtu.be
And this is Bursch's quiet muffler!