I programmed my GT tonight with the tuner and was impressed! I bought the SUPERCHIPS tuner at SUMMIT by the advise of salesman I have dealt with before at the store. I tuned it with the "performance tune" but edited the auto tranny options to "stock" since I have a shift kit installed, set the fan to turn on at 180 degrees, and raised the speed limiter. This tune requires 91 octane minimum but you can set it for 87. This is my first use of a tuner and wish I knew more about the others to compare. All said, it works great with the few mod's I have.