What you want to do to it is essentially what i have been driving for the past 6 years daily, minus the O/D.
Just watch the maint and keep up with it.
The High Ratio tcase isnt a good idea unless you have a really strong engine, even then i have heard lots of bad about using it with the rover 2.25. I have a ton of work done to mine but have been advised against doing it because even after squeezing every ounce of HP you can get (almost) from one it may not perform as well.
They work well with the Robert Davis engine conversion.
great truck!
First but gone: 91 3 door Disco "White Rhino"
77 Series III 88 ex MoD "Shongololo"
Gone and I miss her: 97 D1 5 speed
04 DII
08 D3 (LR3)