I have a 2005 BMW 530i in the shop today and I am supposed to do a bluetooth handsfree cellphone kit. I was able to find the front speaker wire leads behind the radio (a pair of yellow/black and a pair of black/yellow). I can't find the rear speeaker leads or the amp and I can't find the MUTE wire for a factory cell phone. I also looked for a factory cell phone controller but can't find it. I am pretty sure a factory cell phone is an option for this vehicle because on there is an icon button that shows a person talking on a button by the menu key. If anyone has any wire diagrams for this car I would appreciate it, or if anyone knows the color codes for rear speakers and a mute button that would be excellent too. Thanks guys.