Steve,
Finally have the answer... managed to grab a used 2001 Mercedes Cartridge off of eBay and finally have my Snap On MT2500 working..
Played with it for a while this morning and can confirm that it reads only the powertrain... i.e. only the engine and trans. Gives lots and lots of information, allows a number of tests, reprogramming of a new PCM computer, but nothing in the subsystems of the car like SRS, ABS, etc. Communications were a snap... scanner linked right into the car's computer without fuss.
All in all, I still think a good investment... my total cost buying everything used is about 500 dollars.
Besides, I figure that now that I have it, I will never need it!
Hope this helps anyone exploring this option for a scanner.
Regards,

__________________
KenP

1996 S500 W140 Coupe