This product does just as it says it will. Installed it on my 2008 GMC Sierra mainly to stop the lag of power while in V4 mode. Only downfall is that this chip will run you battery dead from the LED lights on it. It suggests unplugging it if your not going to drive it for more than 24 hours.
After a month of solid research i decided to go with Bully Dog. Very easy install, excellent graphics, produces the best information from your vehicle. The Tow tune turned my sluggish truck into a sports car like feel to the drivetrain, great shifting, and perfect use of the 5.3 power band. If you have the chevy trucks made between 2000 and 2007 (classic) you should have this tuner.