The USB connector, Dock connector and AUX in are on one cable.
The wires are together, but could be pulled apart.
I feed the cable up into the armrest box. So they just sit in with where the AUX connector was anyway. (Had to run the aux cable there anyway)
I intially planed to leave a USB stick in the car with all my music on it. But given how awesome A2DP is, I dont bother.
Its no nice just getting in the car, phone in pocket and pressing "BT audio" and having your phone play on where it last left off.
The little display even shows track/artist info!
If you get the MKi 9200, it has a slightly bigger full colour screen. (I prefer the size of the MKI 9100 screen, its easier to find a place for)