Hi,
You could be letting yourself into a load of trouble and expense. Retrofitting the OEM kit can be a pain unless you have all the basics installed like wiring, button for pairing etc. If you want a fully integrated bluetooth solution have a look at the Parrot CK3100-LCD. It will integrate with the BMW radio, mute it and works with its own voice recignition. Cost is about £105 from expansys.com.

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2005 4.4 Sport, loaded
"He who has the most toys when he dies wins"