It is possible in Germany to reprogram the Fuso ECU for power etc., but here in Spain it has been impossible for me in several places.
For the older ones yes, but the latest models are not easy cause you could not have an acces to the ecu. And someone told me, that if you raise the pressure of the injectors to get more power out of your engine, could have bad influence on the lasting of your engine.
excuse my bad English.