Subaru loyale - carb'd vs injected. 1 range vs 2 range.

[GypsysFire]

Hello,
First post here ...
I've been brewing over many ideas of having a vehicle with good efficiency, that goes all over, can easily be slept in and carry more things than one could need.
Everywhere I look, I come back to the 80's Subaru Loyale/GL wagon.
A couple years back, after the tragic death of my 52mpg, 87' CRX, I found myself buying what I thought I never would ...A station Wagon. It was a gutless 87' Escort GL, that got pretty decent mileage. Since then, I'll only but a wagon.
Anyway, I drive a 2000 passat wagon 1.8t and it gets 27mpg Ish, with premium and the right hyper miling tricks...but I'm tired of costly repairs and I'd rather not worry about getting a dent or two.


2 options are available:
1 is an 83' Subaru GL wagon 4x4 5-speed
2 is a 93' Subaru Loyale wagon 4x4 5-speed
Both are non-turbo (= regular fuel (; ), the older being carb'd and newer is fuel injected.
I've done plenty of research on fuel saving, but I need help from some who have experience...

Questions:
I have the option of swapping a 4-speed dual range into the 83', does this have a benifit or drawback for mpg? (Syncros are going out in the 83')

Which vehicle has potential for being more efficient? (I have a pretty good idea of mods for both cars, but if you have experience ....well I haven't tried it yet)

Both cars have ~225-240k miles, but the 83' has low oil pressure and some oil use, but good compression...any ideas why?

Thanks in advance for your help.
-Zack