The device does what it says. It disables the AFM and takes away the hesitation and the sluggishness. I used to have a 2005 NBS Tahoe and I regretted exchanging it for a 2013 NNBS Tahoe due to the sluggishness caused by the AFM. Now I am enjoying the newer truck due to more responsive throttle. I did notice a loss of 0.5 MPG but it's worth it for the truck to not feel like a big slug.
Best purchase yet for my 2012 Tahoe 4WD
Purchased tuner for increased MPG and shift point adjustment (but the latter was fixed with a tire size program). Running 87 tune went from a 12.4mpg avg to a 16.3mpg alongside an AIRRAID JR. & Green filter (in the factory airbox). Also had issues with it shifting into higher gears too quickly & not downshifting correctly. A quick tire height programming fixed it. (even tho I run factory 20" wheels and tires). Speedometer is now spot on as well. WELL worth the $$$ spent. Highly recommended.