Jim,

All I can tell you is that my tech who did my engine said there were several modifications in the new versus old engine...but as I had a complete engine replacement not a rebuild...your situation might be different.I was told that the rods,pistons and head on this engine were all modified.
There is another who has posted here who has 90K or so on a rebuild and no problems.Many people had problems with this engine before the original factory warranty ran out.In that case MB put a new short block in the car under warranty.I have not heard of any of those people having problems again.
But remember a new short block only comes with a 1 year warranty and a complete long block assembly comes with a 4 year 50K warranty
The dealer I went to said they had done a 2 short blocks there before and I live in a city where there are probably not more than 10) 90-95 S class diesels...and curiously there was another having an engine replacement at the same time I was.

Warren
1992 300SD
Columbus Ohio
turner@greif.com