I don't know about a few hundred thousand miles. High miles 603.97x engines whether original or remanufactured are few and far between. The statistics aren't there to make a case. What I haven't read in this or any other forum is that someone got stuck with a bum replacement 603.97x engine from MB. But as mentioned, there aren't a lot of miles of documented user experience behind that statement. I think that one guy who installed the engine himself had some problems but nothing attributable to a design or build quality deficiency.

For what one of these engines costs installed at a dealer, you can build a nice S14 with an SR20DET and do some serious Nismo drifting.

Sixto
95 S420
91 300SE
87 300SDL
83 300SD