My new Meisterschaft GTC exhaust...
Full cat back (LXR, SR, mufflers) GTC with EV wireless controller. 102mm tips.
Did before and after on same day with Mustang dyno. Only got 14hp increase with valves open (501whp; GTHAUS has speculated reasons for this over on the M5 forum, so exact #'s in this case are not too important). Did run with valves closed and power not significantly different from stock. Valve open sound is so mean! It is night and day. Starting the car cold in my apt garage with valves open sets car alarms off. The pitch of the exhaust is not as high as I thought it would be so my best description is freakin mean sounding. There were a few problems I encountered when installing:
1. Finding a good accessory power source in the trunk fuse box (a not always on source), but finally found one after looking at the paper diagram that's inside the trunk fuse box (right side). I can't remember the # off the top of my head.
2. Our first attempt at opening and closing the valves using the wireless controller, the valves would open only partially. We had to loosen up the valves and more or less center them appropriately so they don't catch on any piping when moving.
3. Only one of the two wireless remotes worked. One of the pieces covering the led light on the remote also came off (first impression was - I spent this much for this cheap p.o.s.). We fixed the light covering. I called GTHAUS and without hesitation they are sending me a new wireless box with 2 new remotes. Very good customer service.
4. With the big 102mm tips, it is pretty difficult to align the exhaust just perfect from a left vs right comparison (without one side barely touching the rear bumper portion. Overall, not too big a deal for me. But if you cared enough, you'd notice.
My overall impression is that I love the exhaust look and sound. I know my hp gains were not as impressive as GTHAUS has shown but the sound and look are more important as the car is plenty powerful for me. Here is a rear pic of my car. Any questions let me know.
Last edited by F12M6MD; 01-12-2013 at 08:41 PM.