I will get a patrol 4.2TD inter-cooled(earlier one came non inter-cooled), if they are maintained well, they will out last the chassis easy. They also hold their value because Nissan dont make them anymore and more so because they are such a good japanese built engine. If i had one ill get it tuned with more boost and open up the injector pump. The non common rail or common rail 3.0i are rubbish. Or if you have spare coins, turbo a 4.8i petrol and go nuts
I work @ Nissan so i could be bias.