If it's an SD, you might want the Hazet tools that make adjusting the valves so much easier... and a set of feeler gauges, of course.
There's also special spark plug sockets that have a rubber piece that holds the plugs. My spark plug socket won't hold a screw tip plug (as opposed to a knob tip plug). Gosh, I don't even remember if MBs use 5/8" plugs or 13/16" plugs. If it's an SD, you won't need a spark plug socket... unless it also works on glow plugs.