First post, I've used SO much info from XOutpost since buying my basket case 2004 4.4i about a month ago. Working through things one at a time :-). Years ago I was big into car audio and I have been in the tech space for my entire career so I have comfort in dealing with tech related stuff.
Mine came from the factory with DSP, Nav, and the 6 disc changer.
I just finished installing the current Xtrons unit (this one
https://xtrons.com/bmw-x5-e53-androi...l-4g-ix1253bhl).
I purchased the unit, the 6m cable, and the long fakra cable, as well as a third party 3.5mm microphone. Ran the cables from front to back (admittedly time consuming and a pain, but worth it in the end) and just connected up the cables as expected. Ran the GPS antenna to the top of the dash and the external mic up the A pillar and stuck it to the top left corner of the windshield (didn't need to remove the A pillar trim, just shoved the cables in and they are snug and secure).
I have full functionality of all of the features without installing anything else. The only issue I have found so far is that adjusting the fader from Front to Back doesn't seem to work correctly- it just turns the volume down in the vehicle. I haven't spent any real amount of time messing with settings so it may be that there's a setting that will fix that.
Totally happy with the investment, both $ and time, to add such technology to the vehicle. Feel free to ask any questions about install as it's relatively fresh in my mind :-)