i have a 98 Baja 232 islander that came with a 454 mpi. i have purchased an upper and lower intake from a 454 mag efi, dart rectengle port heads and a general freshening of the bottom end. the mpi setup had a fresh water cooled fuel/vapor seperater on the lower lh side of the engine. the mag setup came with the same thing(not water cooled) on the top of the engine by the intake. Both systems have the high pressure fuel pump contained in them, which one should i use?

Use the cool fuel set up, it is an upgrade to the VST setup because they had so many vapor lock issues with the VST.