Reviewed By Christopher T (Charleston, WV) Reviewed for a 2007 GMC Yukon XL —8/10/2011 6:36 AM
I added new tires and rims to my Yukon XL. It was driving awful until I used the Cortex Programmer. It allowed me to set tire height and choose the 87 Octane tuner as well. I took the speed limiter off too. It shifts smooth and gets better gas mileage than it did before I put the larger tires on. It has much more power and really drives much better. Thank you Autoanything and Superchips. Without it, I would have went broke putting gas in the vehicle or would have had to sell the new rims and tires.