As Sinbad mentioned, it really depends on your application. I don't recall what your app is..?
IMO, both psi & gph are important. High horsepower engines require more gph. And, the pumps ability to maintain steady psi without creating too much pump head pressure. For carb applications @ 4-6psi, you shouldn't need a pressure regulator. The pump that that goes up to 14psi seems odd, it's too high for carbs and too low for FI. However it's probably designed to go with a regulator.
