As far as the kind of lubricant to use:
I use Gleitpaste from M-B. For my M-Bs, it is recommended for a wide array of lubrication jobs on the vehicles. I purchased mine from the dealer (don't have the part number with me), comes in a can about the same size as a can of peanuts, and costs around US $18.00. Not inexpensive, however, it has worked extremely well for me both on my M-Bs and around my house.
As far as where to lubricate:
If you refer to the M-B shop manual(s) for your car, it should show the precise spots. My manuals work this way.