while I do not have a used one,
we have the RPi GTM Exhaust for sale for $3999 (free shipping in the US 48 states)
http://www.bimmerzone.com/BMW_Perfor...GF12M6GTM.html
or if you want it quieter, the GT/GTS
http://www.bimmerzone.com/BMW_Perfor...I-EGF12M6.html
Shoot me a PM if you like to discuss
