What type of driving are you intending to do?
What is your driving style?
I have had a 1993 4/4 and currently a 2002 Plus8.
BIG differences in the cars. Engine performance was the biggest with suspension, tyre size, width of car adding together. A bit like comparing apples with pears.
The 4/4 was nimble and fun. You needed to use revs and gear changes to make fast progress. A great car for a driver who liked reading the road and using the gears/revs. It was standard with no upgrades
The Plus 8 had a chunk more power and much more torque. It can be a bit like an auto if you are just pootling around. It is more planted than the 4/4. Wider tyres, Panhard rod, AVO shocks, roll-bar that has stiffened the car. It is a great tourer due to the power/torque characteristics. For more get up and go...it comes alive when 3000rpm is hit, especially in 3rd gear ( 5 speed gearbox).
My advice is to test both variants if you can. You can then see which one matches your needs. As your cars will be of similar age the real difference will be engine related. Assuming both are the same chassis design not new CX versus original ladder style.
Just be aware when test driving that you should ease your way in to the higher speed, harder acceleration drive! Keep a sensitive right foot!
Personally I would prefer the higher power/torque car as it gives more options for driving style. Trouble is not testing both means a true comparison is not possible. The P4 could well be up there as an option with enough performance to not make a difference.
There I have contradicted myself!