I think the TDi is basically underpowered for the weight of vehicle it is pulling around but no worse than the other diesels fourbies of that vintage eg the 2.8 GQ patrol.
I haven't bothered having the fuel pump tweaks done on but have had a free flow muffler put on which helps with turbo lag.
Only fuelling up every couple of weeks or more helsp overcome the fact they are not a rocket ship.

