Hi there,
I don't think there is many people who work on diesel engine in this thread. Anyway, what kind of engine are we talking about here. I don't think that you can do alot off thing on the new HDI or CDI engine.
One thing you have to understand about diesel is that the air is almost constant but the fuel injected is varied. And on modern engine, there is no way that you can alter the fuel pressure or injection timing manually. Everything is from the ECU. You can't just change the injector because it need calibration and there is just so many type of injectors which operate by different rules.
I think the only thing you can do is try looking for upgraded ecu. ( i'm not sure of its existent). Cheers.