Fuel pressure regulator plumbing?

Cooler gas is cool... i guess.
I went from a deadheaded deal( Holley black) to a big return style fuel system on a weekly raced 9 sec car and didnt see absolutely anything in ET difference.
I dont know how much if at all the fuel was cooler with the fancy return system, but it sure didnt make a lick more power.
I would spend money elsewhere