I have a 4.8is with the full factory DSP Nav unit installed with CD changer and TV module. All I did was run the correct Xtrons cable from the Head Unit to the connection in the rear battery compartment and had perfect working audio.

I believe the Xtrons unit turns on the DSP amp

This is my unit
https://xtrons.com.au/bmw-x5-e53-and...l-4g-ix1253bhl