I haven't seen much in the way of increasing MPG, I don't think that's a very commonly asked thing within this community, but obviously any way to reduce weight would be a start. Specifically, lighter wheels and tires. The premiums weigh about 25 lbs each and there are a number of options that are around 17-18 lbs each. And since it's rotational mass it makes a big difference, but particularly for performance.
@nickbaldwin86 might have something up his sleeve