Yes I read that with some amusement. They were all worried about turbo location, which is pretty straightforward to fix. I liked your V8 petrol fuel carrying calcs.
I would expect a Nissan TD42T to be both slower and worse on fuel than the 5.7L Nissan engines. The TD42 is indirect injection and seriously inefficient. Yes it's a strong engine which can take a lot of boost. But because of the inefficiency it takes a lot more fuel and boost to give the same power.
Many petrol engines are more efficient at rated power than the TD42T is. Same with the Toyota 1HZ. But the 1HZ isn't in any way a tough engine.

