Jay, I see that we are both in the Lehigh Valley. Did you see that 300D at L&T on Airport Road? I stopped to look at that car one night this summer, just to peek in the windows actually. Anything older than 1980 or so will be harder to start because of different glow plugs, unless you use a block heater in the winter. My '77 300D was hard to start in less than 20 deg F weather.
Have you checked Autolex at 15th and Sumner in Allentown? Also, LV Volkswagen gets some pretty nice used MB's in trade occasionally. Happy hunting.