
While I'm not sure how much my mileage has increased, I've had 3 upgrades in the same week with new ones Tires installed, the cooling air intake and edge tuners. Together they increased my highway mileage on my 2006 Chevy Silverado 2500HD from 11 mpg highway to about 18 mpg. Installation was easy and over time even a 1mpg increase for this upgrade would have paid for itself.

π K&N Cold Air Intake Kit: Rev Up your 1998-2003 CHEVROLET/GMC (S10 Pickup, Sonoma) with High Performance: Gain Horsepower & Stay Road Legal (57-3025-1)
9 Review

π Enhance Your Vehicle's Performance with the Airaid 200-919 M.I.T. Modular Intake Tube.
9 Review

π§ Improved Performance: K&N Cold Air Intake Kit for 2007-2009 FORD Mustang GT (63-2565)
9 Review

π K&N Cold Air Intake Kit: Boost Horsepower on 2015-2016 Ford F150 Turbo Ecoboost, 3.5L V6, 63-2592
9 Review