OK your looking for MPG, let me tell you some facts, here.
1) You will never get the best MPG if your throttle is EVER at WOT. If your highway cruising, your throttle is barely cracked open. That means all the porting and suchlike does NOTHING. Porting makes no difference unless your at WOT. So do most of the go-fast stuff on the car does absolutely nothing.
2) For best MPG you want to have the car at the lowest RPM at all times. Meaning that when shifting you get the car up into the highest gear as quick as possible. And also meaning that you want the tallest gears possible. Your 3.90 axle ratio coupled with 14" wheels is a problem here. What does your RPM run at when your at 70Mph? I'd bet it's pretty high.
3) If your running a catcon, then you have very little choice in fuel mixture because while the engine will be perfectly happy running on a leaner mixture, you will burn up your catcon.
4) remove weight from the car. You said you drive for work - well do you haul passengers around and people? If not, remove your seats and put them in the garage.
5) lowering is good for MPG.
6) reduce speed. Sorry to say this but I'll give you the following challenge. For 1 tank of gas, do not drive faster than 55Mpg on the whole tank. Then check MPG.
7) Does your car have a trunk mounted spoiler bar? If so, remove it - those are MPG sucks. Spoilers work by pulling energy away from going forward and converting it to downward pressure.
8) fuel is wasted every time you apply the brakes. Be forward-looking and pull your foot off the throttle way, way, way in advance of an intersection and coast to the red light.