Also don't forget the variable meaning of "rebuilt". I'll never forget talking to a fellow many moons ago who boasted that he had rebuilt his TR-3 engine with a set of open -end wrenches and a screwdriver .... no torque wrench, no ring compressors, etc, etc. I thought for a minute, then asked him how it was running.

It wasn't, and it hadn't run very long.

I am under the impression that MB diesels require considerable precision in rebuilding engine internals, that may not be achieved by an average mechanic -- or even an average machine shop.

I recall another conversation with a German mechanic newly emigrated to the States who was dismayed with the local NAPA machine shop's work, saying the precision wasn't up to his standards, nor BMW's (what he was rebuilding at the time)