We need to see yer sig so we know what truck ya run...however seeing that you posted this in the 12 valve forum I am assuming you run a 94-98..........if this is true than a FASS or FASS II unit wont do you any good at all as the 12 valvers lift pump is driven off a cam lobe and if by far the best fuel supply system you can ask for.
The Fass units are an electric motor driven pump for the 98.5-2002 VP-44 trucks and the 2003-2007 CP-3 trucks
Hope this clears thing up a bit.........I will say that the Fass fuel pumps are some of the best after market pumps out there though, and they have product support second to none