If your truck isn't lifted, I really don't think you're getting your money's worth. I'm not a car person, so I've never cared at all about "performance" upgrades unless its improved the gas mileage or towing performance. I believe the mileage gains are more pronounced in the NNBS because of the V4/V8 5.3 and 6.0L engines, but even then it's only highway mileage that's going to get much benefit.

The improvements are magnified when you've lifted your truck because 1-2 MPG is going to be a much larger percentage, especially with the speedometer being recalibrated.