That part number may not be a ULF. I think that it is a CDMA telematics unit. See this link: http://www.realoem.com/bmw/showparts...=84&fg=10&hl=8

In general, if the price is right, there is nothing wrong with buying a used Bluetooth module. Try to get part number 84.21-6 934 961 or newer. If you get PN 84.21-6 955 522 or newer, those double the phone book capacity. Avoid PN 84.21-6 934 552 and 84.21-6 938 610.

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SOLD
2000 E38 750iL Highline Edition, Upgraded with the lastest 2006 X5 Electronics
MKIV Navigation, 16:9 Display, Bluetooth, TV/Video with Backup Camera, Sirius, and Aux Input