The oil pans are definitely different, IIRC the 4matic version actually has a driveshaft running through the pan to the front differential.

Engine swaps these days are a whole new ballgame compared to 20-30 years ago. I've not done any Mercedes swaps but I did have some problems a couple of years ago when swapping engines on an E36 M3. There were apparently some revisions in engine accessories that required some research and wiring mods. Since so many things are now controlled by computers any changes in idle control valves, EGR, evap emission, crank position, cam position sensors, ect, ect require synchronization to the engine that the ECU is expecting to manage.

Hopefully you'll be OK but its potentially not quite as simple a process as it was in the 60's, 70's and early 80's.

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