MMI Updates: Experiences & Recommendations?

Hello,
I would appreciate hearing about your experiences and reports regarding MMI updates.

What are the arguments for/against?
To be friendly or to be self-sufficient?
"Killing" engine control units... etc.


In my specific case, it concerns an Audi A8 4E, model year 2004, with the "very old" version 0770.
If I want to upgrade to an MP3 6-disc changer or an AMI interface, do I need a software update?

"Thank you."