sarcasm, there's a great way to encourage replies

the big thing about upgrading your pump is the amount of space in your machine.
once you go over 200psi the motor becomes the size of a 2.5lt can of paint. what machine do you have?
if you do fit a bigger pump it might need a bypass valve so you may need a new pipe putting back into the water tank.
I'd go with the induction pump mentioned by Dennis, you can buy them from Ashbys no alteration will be needed to your machine, it has almost the same pump head as a flojet but a slightly bigger motor.
Mike