If you have a 5-speed, keep the RPMs really low. No mods for that. I got a Borla header, Borla dual exhaust and open air intake and it has given me better highway gas mileage. You could try that, if you wanted. Narrower tires would probably do it too, but that's no fun. Driving less does it too.
Hope something here helps.
RN
See Mephisto
