HU replacement on 2003 E320
The current (dead) unit is the factory unit and all components are original factory equipment, so I'm assuming the audio gateway is present.
I would like to put in a double DIN unit (Pioneer D3, Apine IVAW200, or similar). I haven't seen an double DIN dash kits and was going to manufacture something myself for the mounting. Other than the new headunit, I assume I would have to purchase a wiring harness (saw some at Car Stereo Fitting Kits - Mercedes Benz, but looking for any input). Also, with Bluetooth functionality on a new headunit, are there any other requirements after the new headunit install? The iPod connection would also be used.
Will volume control on the steering wheel require any retrofit?
I am debating upgrading speakers and amp but want to get some sound back in the car first.
Any help/advice is appreciated...


Not sure about the iPod interface but I assume it is third party only for Audio 20 but for Comand you would have an MB OEM option.
If your car does not have AGW, it could be expensive and some work to retrofit Comand even without APS. On the other hand, if you do have AGW, a non-OEM HU isn't straightforward. In any case a non-OEM HU and the car integration isn't straightforward.

If I understood right, you have the fibre connector and a 4-pin connector with three copper wires. That is enough for a HU. The three wires are ground, permanent plus and wake up for MOST.
I've understood the basic US HU being an audio 50 without APS. You would then have the AGW at the trunk, connected with fibre to the HU. AGW includes the audio amplifier.



