I got some advice from an Audi tech today on how to DIY for this job. The part I'm looking for more details on is how to remove the existing cover - do I need to pull back the trim on the inside? Any more advice appreciated.

I HATE THAT SPEAKER.

Stupid speaker placement means I'm not going to get good imaging even with an aftermarket unit.

After I put an Alpine head unit in my Volvo 850 and calibrated it, I got real soundstaging and overall pretty f'ing good sound for a car. But with my A4, I'm not even going to try.
:(

leaves all kinds of marks on the door panel.