I have:

Top-Hifi - Harman Kardon Surround Sound System
Audio option: S688A / S677A

Vs

HiFi BMW Upgrade
Audio option: S676A / S674A*

This link shows the difference and how to quickly decipher what you have.
https://www.bimmer-tech.net/blog/ite...-audio-for-bmw

Your YOUTUBE video was great!! Thank you so much. If you don’t mind, could you send me a link to where you purchased your screen from, and any auxiliary parts that you may have purchased as add-ons to give it the quality sound that you were describing you still have?