Reviewed By RICHARD J (Parachute, CO) Reviewed for a 2005 GMC Savana —7/13/2014 9:25 PM
Big difference in power. I get 3 to 4 mpg more when using performance level.
Reviewed By jim f (PHILPOT, KY) Reviewed for a 2010 GMC Sierra —1/27/2016 9:54 AM
Purchased this to get rid of AFM. It was on sale and about the same price as the thing that just plugs into the port to just get rid of AFM. The Xtune can disable AFM along with most features of more expensive tuners. The mileage tune was installed and couldn't be happier with the results. I would recommend this tuner.