I assume that you are talking about the 2.5TD (4D56T). Its a decent engine with nominal wear if cared properly. It will do about 6-8 kmpl depending on the traffic and engine condition. Parts are available, I have not faced any issues in finding parts. If you need to get the hard to find interior trim bits and pieces, just check ebay UK. They break loads of Pajeros there .
If you can get the 2.8L 4M40 it would be even better, coz it pulls almost like a petrol car.