Yes you can. You need to decide if you want to keep the BMW Assist functionality though. If you do then you need to get the dealer to install the Bluetooth/Assist TCU found in 2005 or 2006 vehicles. Its compatible with your car - the dealer just needs to actually read the Service Bulletin on the subject. Note is pricey though. The TCUs retail at around $1200 + installation (1 hr ... even though it should only take about 20 minutes) I'm afraid this is all at the customers expense.

If you don't want BMW Assist, then there is a cheaper option. You can get a Bluetooth ULF module. This will replace you current BMW Assist only TCU. Go along to http://www.bmwnav.com You can get a ULF module from them.

Good Luck !