Best engine option for 3rd gen Pajero is 4M40 2835cc diesel turbo.
A friend have got one in Islamabad, its auctioned from French embassy and in pristine condition, he got it for 29.
Its giving almost 10km/l in city and on highway around 12km/l.
He changed all its shocks and suspension rubber parts and found them easily in Rwp/Isl.
I have got a Toyota Surf 1999 with 1KZ-TE and I have done 50000 kms in last 2 years.
She is doing 8km/l in city and around 10 on long route al hamd o lillah.
Parts are easily available.
I would suggest to give first priority to the condition of any one of them.