I think I'm around 8-10 mpg at the moment - mods in sig.

Just curious if I could do some swapping out of parts, maintain performance, but improve mileage?

STS systems are so cheap now (used), would it be worth selling my headers and roller rockers for example and putting the proceeds toward a used STS kit? I know I would still have to throw some additional cash at it, but would that improve mileage?

Any other suggestions? Procharger?