Fuel Pump (dumb) question
 

How much noise is normal?

Mine is about as loud as a cell phone vibrating on a table when I turn on the key, and just minorly noticeable when running.

(?)

FP whining
 

Excessive FP whine sometimes indicates imminent failure but 'noise' is subjective, especially if you're new to Mustangs. They all whine when you turn the key on and make a slight noise while driving. This is normal.

If the car runs fine then don't worry about it; just turn up the stereo. If it gets hard to start, begins to show signs of cutting out or starving at high RPM's, think new fuel pump.