I have a 10/03 build and had my TCU replaced under warranty a few years ago which effectively gave me bluetooth capability (the old tcu was causing a static in the stereo). They had to reprogram for the TCU and when I got it back it had bluetooth in it.

BMW Assist worked (it would make the connection to the BMW rep for a test call even though I never paid for the service) prior to the TCU replacement.

 

I have a September 03 built 530 and I have bluetooth, my tcu was replaced under warrenty as they could not get my btum to work so the tech put in a bluetooth tcu (bless his heart).

They did however still have alot of trouble getting it to work lots of PUMA cases and a month in the shop (straight month with a loaner) what he found was that all my previous car info had to placed on a floppy disk and then when recoded the floppy was introduced and whoa BT on mine works great.

The only problem I have is the volume the radio goes up pretty loud but the BT is considerably lower parties can hear me just fine but voice to me a lower and the volume is turned up completly I wish there was a way of fixing this annoyance, but I am satisifed