An older diesel would more likely be plug-and-play. To do what you want to do with that Jeep/MB diesel, the most economical approach would be to buy the entire vehicle (assuming that it is wrecked and available at a low cost), remove and reuse the engine AND transmission, remove everything relative to engine management, install in the Stude.

Assuming the engine bay dimensions can hold it, you might be better off finding a rusty old w123 300D or w126 300SD/L with a good engine and start from there.