I would suggest you swap a Mitsu with another Mitsu, preferably from the same generation.
I am using a Hyundai Terracan swapped with a 5VZ, that's the way I bought it. There were so many electrical issues, cross platform conflicts, ECU miscommunications so on and so forth. Osama has sorted all but one which is not too significant. The performance now is outstanding after re-doing all the engine and ECU related wiring, installing O2 sensor, replacing CAM position and throttle position sensors and much more.
I would still recommend you discuss your situation in detail with Osama.
By the way, I missed where the original 4M40 from your car go? Why can't you rebuild the original one? I am always in the favour of a rebuild vs swap.