I had the CPT-8000 in my '00 M5 and replaced it with BMW bluetooth.
Check out
http://www.bimmernav.com - He sells a conversion kit that is plug and play.
You will need to get the Bluetooth ULF from another source, as he doesn't provide that piece. My total was about $600, and it was working in 1/2 an hour.
The bluetooth module also comes with voice recognition - a nice add if not already optioned in your car.
There is a good forum dedicated to bluetooth retrofits here:
http://www.bimmerboard.com/forums/bluetooth
You might want to research which phones work best, as not all phones advertising BT support are compatible with the BMW solution. I have a Moto v551, which works great