As a new owner of a 1994 E420, I know it would be extremely helpful to know, in general, how long certain components are supposed to last. Obviously, this is an instance where the saying "your milage may vary" really comes into play, but I am just looking for general guidelines for the major systems in the car, including but not limited to the top end of the engine, transmission, HVAC, braking system (not pads/rotors), steering and suspension.

I seem to recall seeing some sort of document on the web with this information on Mercedes vehicles in general, but cannot find it now. If anyone has some thoughts on this, or where I might find the web document, I would love to hear from you.

Go to this address:
http://www.mbca.org/MBCA_parts_wear_out.htm

It offers general guidelines on Mercedes parts.

That's the one I saw before. Thanks a lot for pointing it out for me.