Originally posted by Epoch
But I think that better headers should be your next investment,
How many headers does your car have?
I'd go with a good header and possibly high flow cat to complete the airflow part of the engine.
Adding those two to your current list will give your engine a good air base to work off of. Next it would be good to get some semi-aggressive cams, or an intake mani + throttle body and more aggressive cams.
Short answer: I vote header.