In the absence of a better reply, and never having done it, anything can be accomplised

All depends how much work you want to do
Be patient with me, I have been away from land Rovers for a few years now, my last one was a 2000 MY TD5 110 Defender, sold that around 6 years ago
Lets look at a DIY level "bolt on" upgrade ..............
If I were you I would start by comparing pictures of the Range Rover Classic / Discovery 200 TDI PAS box, to your own .............
If the fittings (3 bolt) plus the column and drop arm splines look the same that's a good start
Next up which Engine do you have ? See if the same Engine came on another model with PAS, if so that is what to source Pump, Pulleys and Belt from ...............
Pipes can be made up by any Hydraulics Shop, ask a man with an Excavator who he uses

Buy rubber lined Stainless P Clips to secure the pipework
Buy the easily available round black ZF Reservoir from BMW / Discovery 1 etc ............... Jobs a good un
Keep us posted, interested in the results
HTH
