I am brand new to the full-size SUV game, and I am looking to unlock the full potential of my wife's family hauler. We bought an '08 Yukon XL Denali, and I'm just curious about which of the many handheld tuners you recommend for improving performance and mileage. I'm not looking at doing anything too crazy, because, as I said, this is just a family hauler. I've got the 6.2L V-8 motor with slightly oversized tires, but not planning on keeping them when we need to replace. I don't think we have AFM. Any recommendations on best hand-held tuners is greatly appreciated.