I got the following information from another MB list by James Yuhn:

Just about anything will work, the Becker is a very basic radio and
completely self contained. Just look for a single DIN chassis radio/CD player. Be sure it does not require an external amplifier. Installation is very easy; I think it required only 45 minutes to swap out the becker in my '87 E-class. The wiring pretty much swaps directly to the new head unit, with the excpetion of the alarm wire - I think this was left disconnected.


I selected a rather basic Blaupunkt unit. Just a radio and indash CD player - no remote controls, no CD changer control, nuthin' fancy. Fits the car's interior reasonably well. I'm afraid I don't know the model name, and it was 7 or 8 years ago anyway. Just avoid the units with garishly colorful displays that seem to be all too common these days. Other than that, these are pretty much commodity items - you won't be able to tell the difference
one from another.