I want to make an uneconomical car get good gas mileage (2011 Mustang GT)
 

So I currently have a 2011 mustang GT and I am looking for lightweight, aerodynamic wheels and high efficiency tires. Stock takeoffs would be amazing. My current lug pattern is 5x4.5 or 5x114 mm. I have gotten 27 miles per gallon out of this car on road trips, but I would like to make that my daily driving average. I am planning on putting a 3.15 rear end gear in the car and possibly lowering it. in a perfect world I would be able to take off my eco wheels and tires slap on some drag radials and go have some fun with e85.

The 3.15 rear is probably just about the best thing you can do.

Unless they make a lower ratio...

An economical tune might be an option.

If you are able to remap the fuel tables you could run lean burn while cruising down the highway.
If you can go from close to 14.7:1 to more like 16:1 that should give you at least 10% more mpg

I do have HP tuners. Hmmm

Just make sure you run a normal fuel table when manifold vacuum more than 7 or 8 inches of Hg.
You need a normal air fuel ratio as you get anywhere close to wide open throttle.
When I did my lean burn the secondary jets opened up starter dumping fuel into the intake around 8 inches of Hg and I never burned a valve.

I would use caution when adjusting the a/f ratios. I dont know ford very well but I assume there are cam phasers being used and you should be able to control then with an hp tuner. Anything you can do that will reduce pumping losses (by increasing the throttle opening) at cruising speed will help. E.I. taller gearing, higher a/f ratio, changing cam timing, etc.

How much highway driving do you do?

You can make your current tires more economical just by increasing the tire pressure.

Wrap your headers and if you're lowering your vehicle, consider just lowering your front end to establish positive rake.