I owned a 603 for a number of years. I've always been curious about the 606 series of engines. I've owned a 1995 gas w124 and had lots of electronic issues with the ASR unfortunately. I could never track it down and ended up selling it after lots of limp homes. I wouldn't want the diesel version of the M104 if the 606 is it.

EDIT: To say no harm; no foul towards gasser owners. They're great cars no doubt. I prefer the least amount of complexity in an older vehicle no more no less.

That said, would it be practical to transplant this powertrain into another rear wheel drive vehicle? I have no idea on the transmission sensors and inputs. I've heard that the 300d turbo transmissions are pretty bad as far as issues that leave you on the side of the road. How much input is needed to have this engine and transmission actually drive in another vehicle.

I'd suspect:
-tps
-vss
-shift lever
-brake signal
for transmission

and
-pedal for the injection pump control
-mass airflow sensor
-o2 sensor?
-turbo boost pressure (MAP?) in place of the Alda in a mechanical pump
for the engine.

__________________
-E300d '99 350k
-Suburban '93 220k
-TDI Jetta '03 350k
Sold
-F250 '96 7.3
-Dodge Ram 12V
-E320 '95 200k
-E320 Wagon 1994 155k
-300d Turbo '87 187k miles
-E320 1994 200k
-300d Turbo '84 245k (sold to Dan62)
-300d Turbo '84 180k
-300sd '80 300k
-7.3 Powerstroke Diesel 15P Van 500k+ miles
-190d '89 Non Turbo 2.5 5cyl 240k (my first MB)
Tom's Imports of Columbia MO Ruined the IP in changing leaky delivery valve O-Rings - Refused to stand behind his work. Mid-MO MB drivers-AVOID Tom's.