Selling my hand held Diablo Predator Tuner for my Chevy Avalanche. It comes with the ability to amend tire size to correct speedo, error code reading / deletion, timing changes etc... as well as 2 preprogramed performance tunes. Used on my 2007 Avalanche and gained a nicely improved throttle response and real world 4-5 mpg increase. Here is some official blurb: These DiabloSport Predators are state-of-the-art, hand-held flash programmers. From original factory calibrations, the Predators allow you to quickly choose from multiple dyno-proven performance to economy calibrations, including advanced vehicle diagnostics, real time monitoring, and precise logging capabilities. The DiabloSport Predators include easy-to-navigate, user-adjustable tuning parameters to suit your specific needs. Advanced vehicle diagnostics will read and erase fault codes, providing concise, viewable text explanations. Real time data monitoring and precise logging allow you to make intelligent tuning and troubleshooting decisions. Additionally, these changes may be easily viewed through your PC with DiabloSport's interactive software downloads Regarding 2007 models, this programmer will not fit "old body-style" Silverado and Sierra trucks. This programmer is only compatible with the "new body-style" Silverado and Sierra pickups. On the trucks, the 8th digit of the VIN can not be a "G". Some vehicle applications require a custom tune or programmer updates before installation. Please read all instructions and check the manufacturers website for these tuning updates before installing the programmer on your vehicle." Price is $165 cash ftf or $175 shipped.