Well, I'm one up on the MK4 Owners. Android Auto Wireless works for me! My wireless interface box finally arrived after waiting for it for 10 months!
For those of you wanting to do the same thing, it should work with Bolero, Amunsden and Columbus systems. The screen shot shows it working on my retrofitted Columbus system with MHI2_ER_SKG13_P4526 firmware. On Bolero and Amunsden it should work on SOP4.x hardware with 0478 and above.
Download the app onto Android. It works best with Android 10 and above. Connect it up, enable developer mode in AA, enable Wireless and connect up the device. You also need to enable the VAG crash settings to get it work in Wireless AA app. You also need to update the AAWireless box to version 1.71 (it won't work on version 1.60).
You need to wait 40 secs for connection and for any reboots. To get the best audio settings, go into AA settings and enable Auto Resolution and enable 48khz Audio Rate.