So right now I'm looking at the
Bully Dog 40410 Triple Dog GT Gas Gauge Tuner Adjustable
It is usually priced $300-400 online, and I've heard it will add horsepower as well as 3-4 MPG! I might put this on my wish list, and get it put in before our big trip this summer. Stay tuned! After I get it in, I'll put up a review.