can anyone tell me weather a s2 fuel tank will bolt into a s1 ..... as i cant find a good s1 fuel sender anywhere but i can have a s2 tank with one for free

 

Yes they bolt in but if i remember correctly you need to mess around with the filler pipe so you cant run with the original cap, but i stand to be corrected.

 

The tank will fit straight in, but then the troubles only start...

The S2 tank has a push in filler neck, but you can't use a mk4 filler neck because the holes in the rear quarter panel are different.

The sender is on top of the tank in the mk4 and it operates very differently electrically. The mk4 has dual potentiometers whereas the mk3 has one and a separate low fuel switch.