When I did my install on a 2004 X5 with nav without DSP, I had a quadlock connection and you have to burry down to the radio to make the connection.

Handy hints:
1) Don't leave the ignition on whilst you do the install, with Air con on etc....I flattened my batter...Doh!

2) Make sure the Quadlock connection is secure...hold the sides whilst applying the mechanism...otherwise it appears nothing works.

3) Ensure the black sub socket (in the back of the quadlock) goes back into the radio...otherwise you wont get NAV/Tape audio.

4) Make sure you get the latest firmware version...I got EB2....to install it without the menu look at:
http://support.dension.com/support-c...mod_id=2&id=55

Apart from that my install went very well and it is very worth it.