You might want to check www.bimmernav.com
Lots of info and adapter kits are available for the various E39/M5 phones. He only sells the adapter kit - not the ULF, which you would need to get from a dealer.
You might also look at http://www.bimmerboard.com/forums/bluetooth, a good forum for M5 bluetooth upgrades.
I used the bimmernav kit in my '00 M5 - it was literally 1 hour to get it installed.
Lots of info and adapter kits are available for the various E39/M5 phones. He only sells the adapter kit - not the ULF, which you would need to get from a dealer.
You might also look at http://www.bimmerboard.com/forums/bluetooth, a good forum for M5 bluetooth upgrades.
I used the bimmernav kit in my '00 M5 - it was literally 1 hour to get it installed.