Well that is one of my complaints about FiTech, too many places to get tech info. I too was skeptical, but I did find an official post from them stating to have a line from the FCC port to vacuum. I tapped (T'd) it into the vac line to the reg on the side of the throttle body. The other port on the TB is now used by my vac advance. The engine vacuum will reduce the pressure at idle as an other means to reduce fuel pump deadheading at idle and overheating, also they have the pulse width volts to the pump reduced to 40% to reduce pump heat and cooking the fuel in the canister.
FYI,
Marion