Just buy a bluetooth compatible Assist unit from a newer BMW. You may need the bluetooth antenna which is inexpensive. It will automatically add bluetooth functionality and integrate beautifully with your factory system.
GT1/ISIS/MoDiC = Factory authorized diagnostic system used by BMW dealerships across the world.
NCS Expert = BMW Factory R&D programming tool available on the internet (not intended for the public and not available to the dealership network)
OEM = Genuine BMW part only available from a franchised BMW dealership.
DME = Engine Management Computer