Increasing lift pump pressure

[4x4_Welder]

I've been thinking on how to get a cheap power increase, and have to wonder what would happen with increased fuel pressure. I know as the outlet fitting spring gets weak, the pressure drops, and performance is lost, but what about installing some sort of regulator on the return line? I'm not sure what the lift pump is actually capable of putting out, but say it's at 3psi now and I regulate it at 8psi, would it be reasonable to assume it'll gain a bit of power?