I have the full cat-back Meisterschaft GTC exhaust on my M6. You can see and hear it over on the M6 forum (
http://www.6post.com/forums/showthread.php?t=791125).
With the valves closed, I do think it sounds much more exotic. Of course, with the valves open, it has a much more deep note. I chose this exhaust for a few reasons: HP gains posted, loudness of sound, pipe diameter (I think its the biggest at 90-92mm), valve option, and rear split exhaust tips (I thought they looked cool).
Yo Vic55, did you wrap your rear spoiler? My local shop said it may be difficult to get the wrap to apply properly at the very edge. Is that true?
M