Mike, glad my page . . .
was of some benefit to you: that's why it's there.
At the bottom of the page, click on Part Trackers and put out a request for a USED part. When I had trouble (about three years ago) with the DI Module (Menu #5), I got a replacement (used) from a NYC junk yard for $200. New part is $1100. Still running strong.
1)Has anyone on this forum had any success at getting MB to warranty such items? <--- If your car is "starmarked", you should have no trouble but if not, lots of luck!
2)Is there ANY information actually stored on DM, any reason a 'recycled' part couldn't be plugged in? <--- The DM purpose is to interface with all of the other modules and serve as a central point to read DTCs using the LED/SW combo that was deleted in late 94. With that LED/SW, one (anybody) could quickly read stored codes. My '94 still has one. As I've stated above, a used one (that's good) should fix you up.
3)would a recycled DM from any other Mercedes be interchangeable with mine? <--- yes, if it has the same part number.
Regards . . . . JimF
'94 S500 Cpe
Visit my Mercedes Web Page