Here's a good write up on how to rewire your fuel pump.

http://1300cc.com/howto/how2/rewire.htm

The problem with our fuel system is that it's powered through the whole car. Let's say it's night time, your blasting some music, and you have the A/C on. With your head lights and everything else on, it's taking a lot of electricity. Then, you feel like getting on the throttle, your fuel pump will be begging for more voltage but will never get it, resulting in less fuel flow.

With this fuel pump rewire, the fuel pump is powered directly from the battery and it won't matter what else you have running.