Fiat 2.8 jtd is a great engine, if Mercedes made that engine everyone would rave about it. I think the 3 litre is even better though.A lot of stuff there would not relate to a Fiat 2.8Jtd
A basic diesel engine needs fuel, injector pump and compression, then it will start and run.
The rest is tarting it up. I know from my Mercedes OM 636 in my boat which was basically designed by a German PoW in UK in WWII, engine built in 1978 and is still running in the boat in 2023.
KISS