[LostCause]

I second the ScanGauge. It will take awhile to recoup the investment, but seeing instant/trip mileage is invaluable.

I would only switch out the wheels if you have them or can get them extremely cheaply. Heavy wheels are only really going to hurt you during acceleration. Their effect will be neutral on the highway.

Apart from driving style, which you seem to be doing very well on, your greatest gains will probably come from doing aeromods. I'd push in the radio antennae, get some coroplast to mock up some fender skirts and a grille block, start thinking about an undertray, and lose the passenger mirror.

- LostCause