We have a 3.1L in Australia but they are not that popular as the 3L-intercooled model, I heard this model is suffering from faulty injectors and has not been sought after.

Pajero has 2.5 intercooled t/diesel until 1992 the after that is the 2.8L. This one has more grunt. This link has more info on it
link

The Trooper (or jackaroo it being named here) is better for off-road and Pajero is more for suburban.

Regards,
Trong