Changing to a bigger fuel pump will not require a tune.

The pressure seen by the engine is controlled by fuel pressure regulator. The pump pressure is only up to the fuel pressure reg. 255 is a weak pump and the OEM fuel pressure regs should handle this.

I have a easier test to determine fuel pressure, its not 100%. Dont start the car, just keep on turning the key on and off position on the key. If its the pump it will sound funny, if the sound is consistent its all g.

My fuel pump got louder and made unusual sounds before it died. Took it a few months to die, but it died eventually. Other symptoms are rough idle and stalling when taking off in 1st.