as gadget said, I chopped a mk4 piece where it drops in the tank and sleeves it with a mk3 filler, I then bought a metre length silicone pipe fir the tank breather,I was given a impress updated pump and it fitted lovely in the tank, make sure you have the efi pedal and cable,I only used a internal tank as I wanted to do away with the pump from underneath to make it neater and got the tank for £20 and Fuel pump given off a mate so for me it was a no brainer