What to look for when buying an engine.

After much thinking I have probably landed on getting a low mileage 2018 5.7 from a truck. Looking at using the PCM P5160105 from the Crate Hemi Engine kit and modify the harness. Some info about it here: Chrysler SKIM Thread 2.0 - Page 2 in post 28.
Looks like the Power Distubution center (PDC) in the kit is part of the harness kit so need to look into a substitute for that one. Still in the planning prosess to see if it can been done this way, and if I would save money on doing it that way...