german van!!!

hi all i'm in britain (cornwall) and driving a 2007 vw t5 1.9 turbodiesel transporter.
i already get around 40-42 to the gallon and i'm about to hook my dry cell into it... (after i can get enough money together to buy a power supply to test it properly). any one got any ideas /comments about how to go about it and what electonics i should use. the van is virtually fly by wire and i'm dreading defeating all the engine management stuff. i know most of you guys are stateside and don't do small diesels but i thought i'd ask..