I believe "desertdevil" has very nicely commented on all your points. Last week i heard this thing from someone else also that his jeep was excellent and was in very good condition. (By the way, i salute "desertdevil" for his efforts in maintaining his pajero this way.)
Just keep one thing in mind, "HAVE FAITH IN WHATEVER YOU HAVE", and maintain your pajero in its original or near to original form. I have kept both 3 door and 5 door pajeros with 2400cc intercooler turbo engines but they were both 93 models. One of my regular hunting partner had an 89 model 5 door 2400cc turbo engine with automatic transmission. All these three jeeps were very roughly used with no complaints.
U can put in the 2400cc turbo engine in your pajero. It will be able to run on 120 on motorway with no issues. Very economical and smooth drive. The parts are available and cheap. And as far as the re sale is concerned, good condition vehicles always have good resale, provided you maintain them in their original or near to original form.
Putting in a toyota engine is not at all recommended because of too many modifications.
Brother i would request you not to be sentimental here. As you said and i quote,
"believe me I've seen bonnets going up on the mighty LCs while I whizzed past them on my 'ol jero!!!"
If a vehicle stops on the road, a tanga trolly will also pass it for sure. There is nothing outstanding in passing by a stopped vehicle. We are here to encourage new people to love all 4X4s in a positive way. And to get knowledge of all brands. Yes, positive competition is a part of all this but we should not make it a routine of objecting other brands all the times.