Kelleners Sport Exhaust
Made in Germany by Eisenmann
4x90mm Round tips
Full system or rear muffler only
http://www.kelleners-sport.com/en/Ne...ust_M5_F10.php
"Even if the new BMW M5 (F10) is still quite rare Kelleners Sport already offers a complete exhaust system with valve control for this new supercar.
Kelleners Sport has developed a valve system that has been integrated in the rear silencer. This allows it to be opened or closed automatically, depending on the rev and speed of the car.
That means that the valve remains closed by a cold start in order to comply with the legal noise regulations. From a rev of approx. 4.000 rpm the valve opens and delivers a much more sonorous exhaust sound."