These Supersprint Race Mufflers only have about 17,500 miles on them.
My recently purchased 2006 M5 came with a Supersprint exhaust (including X-Pipe), and while the overall sound is fantastic ... it was too loud. So I have put the stock exhaust back on. (I already sold the X-Pipe ... the loud part - sorry).
Price for the two mufflers is $850 plus shipping.
Here are some pics:
LEFT SIDE MUFFLER
RIGHT SIDE MUFFLER