My 1987 300D has 205k on it with the #14 head. It runs excellent and has never exhibited any problems whatsoever. The radiator hose is soft when cold and the coolant (MB only) is replaced regularly. BTW, the car never goes much above 80 deg C at any time. It really is a nice engine and I agree with everyone else.. don't let a #14 head scare you away. There are too many good ones out there as proof!
Oh, I think many problems on these cars are indeed related to the failure to cool the engine down after running at high turbo boost. I always make certain that it idles for at least 30 seconds before shutting it down. Especially after a run on the freeway....