Tap into Head unit to get raw Audio bit stream?

[oztme]

Hi,

I have an X3 with a terrible stereo. No tweeters. Very ordinary.

I want to pop the lid on the CIC (NBT/EVO?) and on the circuit board, find a test point, or somewhere I can tap into to get a raw bit stream, prior to any amps/crossover inside the head unit (note I do not have the BMW amp in the back that the hifi/top hifi options include)..

I am an electronics nerd. Can design circuits, design multilayer circuit boards, have SMD and reflow equipment, microscope etc.

Has anyone done this before? The UI is great, the Android Auto works great. I just need to get that bitstream....

For example, in the attached picture, I want to find the points inside the head unit where the signals are as shown by red dots in picture...

Cheers + thanks,
Scott.