Bowers & Wilkins Booster harness install on BMW X7

This overview of installing a B&W harness will allow me to hook up an external amp and sub to my BMW X7. I couldn’t find any details about what a “Booster” was or its location. It is inconveniently located on the back side of the RAM (the main factory amplifier the head unit plugs into). The adapter must plug into the Booster, which is a 2nd amplifier. The Bowers & Wilkins RAM and Booster are behind all the trim pieces in the rear left quarter panel. The RAM is accessible through the side access panel but not the Booster. This video shows you how to get to the Booster to unplug the factory harness (white plug) and plug in the B&W adapter. I did this vs. cutting/splicing my factory wires. I am working on upgrading my 2021 X7 M50i while keeping most of my Bowers & Wilkins (Option 6F1) 20-speaker setup. I am adding a sub, JL Audio 13TW5 CS113TG-TW5V2, and amp R2-1200x1 with an LCI2-pro; I also intend on powering my under-seat 8" subs with a bridged Rockford PBR400X4. I did not intend to splice into my factory wires, so I came across this B&W adapter. The adapter has some excellent features besides not needing to cut the factory wires; it has two different options: you can use one or both. One is to power the under-seat subs externally (or you put the connector option to allow the factory amp to power the under-seat subs), and the other/main feature is to tap into the subwoofer line-out signal, which goes into the LOC. I&on the fence about externally powering my...