[elhigh]

It sounds to me like you're mostly using your car around town. If that's the case then I wouldn't recommend going to taller tires, though making the switch to alloys and narrower tires will probably pay some dividends. Reducing the rotating mass will allow the car to accelerate up to speed more quickly, and of course you already know about reducing the frontal area.

Not spending a lot of time at high speed does take the aero improvements to a somewhat lower priority, but you sound like you're already on your way and I sure don't want to dissuade you. If you're up for it, by all means: go for it.

It sounds to me like you've hogged out a LOT of unnecessary weight. Any idea how much? And how much the car weighs now?

Anything you can do to improve your information profile is good. How much load is on the engine, operating temperature (very relevant when you start looking at grille blocks), instant MPG of course. Absolutely +1 on the Scangauge or Ultragauge, it's the thing that makes "adjusting the nut behind the wheel" so much more effective.

For my part I purchased a Torque app for my phone and paired it with an OBDII bluetooth adapter. It's proved useful in my Honda, and now my son is using in the Subaru (up 10% already, just one week!) So there are ways to do that and not break the bank.