i cud do with a hand, dont understand what sum things are and i dont know what i need and dont need, if sumone whos built one can point me in the right direction that wud be great.Jimfoo has already helped me alot, i understand you need the cam plate and springs off a tdi and obviously the bigger the pump piston the better.then i get a bit confused after thatthis on my aaz pump, what is it? do i need it?Leave it hooked to power when running.this is on my tdi pump, what is it? do i need it? if i dont have it will it mess up the ecu?Put the parts in the AAZ pump to make an M-TDI pump. So that way you won't need to worry about that part.this sping sum how advances the timing on the tdi, how exactly does this work? im guessing i need this on the M-TDI pump?is there anything else i need to do?also can you buy 12mm pump piston/ head? if so how much and where from?