A friend of mine got an exhaust from Eisenmann to his E55 AMG.
He went back to AMG in Germany and showed it to all of the staff and they were very impressed with their quality.
Took the liberty to check what they have for the RS6.
http://www.eisenmann-technik.de
Well, the picture might not say much but LIFE IS GOOD -
Here's the sound clip!
I want to hear this!!!