So my fuel pump isnt cutting it anymore, my motor goes limp after a (low) certain RPM range. I am looking to the future at whatever motor swap or upgrade that I will be doing and have decided to get a pump that can support more power. How much can the stock pump handle? In selecting a pump, you must choose what pressure range and GPH you want and i'm not sure what each of those figures is concerning. What i'm thinking right now is that pressure is good for high RPM and GPH is a general idea of how much power it can handle. Am I on the right track?

Your right insofar that each gallon of fuel has a certain amount of potential energy for a given horsepower.
You need the correct pressure as the injectors are rated for certain flow(volume) at a certain pressure level.
Too low pressure,and you have not enough flow through injector.
Too much pressure,and you have too much flow through injector.
Generally you will size your injectors for the flow you need at a given rpm/horsepower,and leave the pressure alone.
I like to raise pressure a bit and recalculate the injector personally(for better atomization).

If your running lean at higher rpm's/load then you are probrably running into a flow problem.
Check your fuel filter,as it will restrict flow when it clogs and not pressure.
Otherwise,if your looking to upgrade here's a thread I posted up (there are several by different people if you use search.)
https://www.fiero.nl/forum/Forum2/HTML/105002.html

[This message has been edited by DefEddie (edited 02-02-2010).]