Kensington Liquid Aux BT $70 Amazon Gold Box deal until 2 PM PDT
 

August 9th.

The advantage to this unit, other than being a lot less expensive than BMW BT units, is that it will connect wirelessly to your phone or BT enabled PMP through the 2.0 stereo protocol. I know the E53s don't have that feature. I'm not sure about E70s. It does require AUX input which is easy to add to E53s (after a certain production date?).

It also has a USB port charger so you can use it as a phone charger for longer trips :)

There's also a $15 rebate available (good until the 11th).

Too bad there aren't any customer reviews :(