4.6 fuel injectors

I just put a cold air intake, 75mm throttle body, 75mm intake plenum, 1 inch throttle body spacer, and 1/2 inch intake spacer. Now i think i am sucking to much air and not enough fuel. I want to get bigger injectors but don't know how big to go without having to replace a fuel pump and get a regulator? Can someone help me!