This guy did a great video:
https://www.youtube.com/watch?v=MdCQg2tJFYg&t
There is another thread it was discussed in recently (see the end) :
http://986forum.com/forums/performance-technical-chat/28342-fabspeed-exhaust-too-loud-4.html
I have maxflow w/ headers but have not had supercup to compare.