If I get aftermarket exhausts, headers, etc for my WRX, would that affect the gas mileage? I'm trying to get as much power out of my car without negatively affecting the gas mileage. What other mods would you suggest?

Thanks

Driving style also effects gas mileage, did you take that into consideration?
Obviously those other things will have an effect too.

You're not gonna make any serious power without affecting your gas mileage. You gotta burn gas to make power.

You might not see any change with those new parts, because it will run a little more efficiently. But then, you're not gonna make any real power with just those parts either...

Try nitrous, at least then you're only affecting your gas mileage when you're spraying.

If you get an aftermarket ecu, which you will once you get into serious modification, you can adjust air fuel ratios, turbo boost, etc and dl maps that you can change between for say in town driving and racing. does good for gas mileage long as you dont have it set on a race setting all the time.