Just wanted to bring this up in case it hasn't been discussed before..
On some of the older diesels, if you experience the common leaking main fuel filter housing problem, there is a new modified assembly available from Mercedes. Rather than a sealing washer at the top of the bolt, it just uses two o-rings. The housing is also changed slightly. All in all, I think the whole setup is about $35 in parts. Definitely a recommended modification.
Precision Motorcars, Cincinnati, Ohio
'67 250SE Cabriolet
'79 6.9 (SOLD)
'93 300E 2.8