So I got completely geared up to do an install of a powered Audison APBX 10 AS2 subwoofer w/ the TechnicPnP harness, and realized that having the 5 zone climate package appears to significantly complicate the install. The rear HVAC unit appears to be completely obstructing the factory amplifier, which you need to tap into for the wiring harness.
Update: found this thread with instructions for removing the rear trim panel in order to access the amp:
https://g07.bimmerpost.com/forums/sh....php?t=2011815