Louis, thanks for the input.
Another change i did not think about before is that the antenna would have to be routed from the trunk (where it now terminates) to the new head unit, if I should go that way. Sounds like too much $$. I think I will stick with the original system for now.
Partly because, I found out from Becker that they charge only $175 for rebuilt radio on an exchange basis (both pieces, head unit and tuner). I had expected it to be a lot more.
Maybe once I have done that I will think about replacing the speakers, which are 11 years old.

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DavidB29
1992 300E with ASR
35 years of Diesels until now!