Assuming you don't have a fuel pressure gauge, and can't easily fit or borrow one....
Can you check the voltage across the fuel pump's terminals (pull it out again, still plugged in, start the car and put a multimeter across the terminals when you turn from ACC to IGN with the key)?
How full is the tank (maybe the pump is too high in the cradle, or the cradle was not refitted properly)
Do you have a programmable ECU that may have been tuned when the old pump was failing?
Is the sock on the bottom fitted properly, and is it clean? Maybe replace the fuel filter as well