Particularly for the winter, get rid of the CAI! You might even look into a WAI, taking warm air from somewhere hot in the engine bay like around the exhaust manifold. Less power, true, but you'll be reducing the pumping losses resulting from pulling air past a nearly-closed throttle plate at cruise.
Pump those tires up to the max number found on the sidewall. Lower rolling resistance is good!
Try ditching the wing. There's a good chance that will help.
Consider a belly pan.
Consider wheel skirts.
Consider a grille block, particularly with the cold winter weather. (OK, let me put that "cold" in quotation marks, as you folks in TX don't get much colder than we do in CA...
)
Do get a ScanGauge. That can let you make small changes to your driving which can improve your fuel conomy more than any mechanical mod you can hope to make.
-soD