T4 2.5 TDI ECU Remapping?

[Pundit]

I was wondering if anyone can provide info on getting my 2003 T4 2.5 TDI remapped in Melbourne?
The UK forums seem to have plenty of info but I'm not finding many options in Australia.
It appears that up to 50% increases in HP and torque are possible after fitting Bosch .216 injector nozzles while maintaining or even improving the fuel economy (under normal driving conditions).

Also what about add-on tuning boxes?
Are any of them any good or do they just fool the ECU into running rich? - TIA