Low RPM's Power?

Are there any mods I can do to improve low RPM torque in my '99 Civic EX auto with d17 engine? Other than forced air? I already have a cat-back and an intake, but both seem to help only with high rpm power. Any ideas? Would a header make better power in low rpm range or is it going to really help with only high revs?

I guess I am answering my own question here. Maybe that's 1.6 liter displacement motor with VTEC is designed for. I just don't want to spend thousands on turbo, or supercharger...

Did I mention I have an automatic?

Drumboy69