http://www.e90post.com/forums/showthread.php?t=487780
Here is the extracted paragraph, am more focused on the last sentence:
"The latest range of BMW Performance products also comprises an attractive complementation of the BMW X5 and the BMW X6 models. From the spring of 2011, a BMW Performance Sports Silencer will be available for the models BMW X5 xDrive35i and BMW X6 xDrive35i. The stainless-steel sports silencer emphasises the characteristic acoustics of the straight-six power unit featuring BMW TwinPower Turbo, at the same time ensuring a drop in exhaust back pressure. Furthermore, the oval-shaped, black chrome tailpipes give the rear end a highly distinctive appearance."