Generally speaking the explorer chassis wise is the same from 97-01, with similar towing capactices, etc. All years 97-01 all have the same SOHC 4.0 litre engine and 5R55E 5 speed automatic transmission. All have 3.73 geared limited slip rear differental. All except maybe North Face have Self Leveling Rear Suspension. 79.5 litre petrol tanks. Mounted on P255/70 R 16 tires. All come standard with everything electric, electric windows, mirrors, seats passenger and driver, sunroof, central locking and cruise control. Standard A/C. Only optional extras on P, R, S, T Reg models where metallic paint and leather seats.
The P and R reg ones with the in a sense '1st generation' that were imported into the UK, very chrome laded, which i like. Large LED 3rd brake light. P reg ones have a separate rear washer bottle to feed the rear wiper. Fixed aerial, digital clock. Radio with tape, no cd on most models. Number plate on left hand side on tailgate, tailgate handle to open boot/glass, unlike S and T, which has a button for glass, and handle under number plate lights for boot.
The S and T reg ones were the '2nd generation' starting to move away from the chrome with alloy wheels, but still maintaining chrome front and rear (slighly different) bumpers. Plastic mesh at back of grill. Different tailgate (number plate in middle, instead of on left like P and R ones, no taligate handle, etc.) and different 3rd rear brake light. Electric aerial, different padding one steering wheel, no digital clock, etc. Different radio, cd.
The V,W and X reg ones were the '3rd and final generation' imported into the uk, labeled 'The North Face', quite different from the 1st and 2nd gen ones, basically a face lift version. Colour coded bumpers, plastic front bumper with fog lights, instead of driving lights. No bucket seats like pervious in front, standard seats with moveable headrests in front. Heated seats, with manual lumbar support, unlike pervious which has motor lumbar support. I believe they have side airbags. Rear radio controls. Wood effect trim over radio console, etc. Most came with mulit disc changer, which is put in storage space in boot.
I have an R reg, 1997, which i am very happy with, personally having though about it i quite like the S and T reg ones with the different rear tailgate, however i perfer the chrome wheels to the alloy ones. It's up to you based on these type of facts, go look at some. It would be better to get one that has already had the OOM12 kit installed, which solves among other things, a rattley front primary chain rattle, but you could buy it and then get this done. Check transmission fluid for pink, not brown colour. In terms of mileage the lower the mileage the better, gernerally speaking the majority of explorers are lower mileage, with the minority being up in the 100,000s. I bought mine with 42,500 on the clock. Personally i would stay away from LPG, because of the extra servicing requirements, issue of wear the spare tire has gone, power loss and wear issues, etc.