2004 Chevy Suburban 2500 4X4 6.0 Liter
Used Cortex Programmer with, K&N intake, and Magniflo muffler. Around town MPG improved 1-1.5 and Highway about the same. More power, shifts are smooth and engine sound is awesome. Programmer was easy to install and I am not a car buff. Once you program the computer you un plug it and are good to go.