We've used the Diablosport Intune on several GMs for this specific function. You have the option to leave the programming completely stock while diabling AFM or you can install performance programs loaded on the device. Most vehicles will also have options to program the TCM, adjust idle, speed and RPM limiters, and program tire sizes as well. You can also program multiple vehicles at $150 for each additional license. And this tuner is CARB aproved by the way.

James Kuhns
Owner/Technician
Auto Tech Solutions
Chatham, New York, USA