search around on here,theres a full how to on tuning the 300tdi manuals including the turbo boost,intercooler and fuel pump mods,a few things can help you save on fuel, might just be mine but after fitting my snorkel and straight through exhaust mine seems to be better on fuel, also the 300tdi lump seems to be better on fuel between 2000 and 3000 rpm,sort of mid boost i guess.