Used to have stock V8 pickup (3/8") through a Holley Blue mounted outside the car, basically under the rear passenger seat, through 3/8" lines to a Holley Blue reg in the bay, single 3/8" line to 750DP, and another single (out of the reg-two outlets) to the nitrous.
That made 234rwkw on Hallam Performance dyno. But had fuel supply issues top end in 3rd and 4th (no nitrous
Upgraded a little (still doing more) to 1/2" pickup, 1/2" lines to Holley Black mounted in same position, 3/8" lines to High Flow Alcohol Holley Reg in the bay to a single 3/8" to 750DP.
This combo to date made 250rwkw again on Hallam Perfromance dyno, but still a few top end fuel issues to sort (fuel pressure gauge in cabin). Hopefully 5/8" pickup, to pump, 1/2" lines to reg, double 1/2" lines to carb should sort out the problems.
Oh, I usually run around the 6psi mark.
PS. like brenx says, if you rubber mount the Holley pumps at both the bracket and around the pump you will hardly hear it. Been there, done that