Our performance tuning for the 2004-2006 GTO typically yields 15-20hp and 1-3mpg (stock vehicles, more if modified), as well as better part throttle response, driveability, and more pep off the line. We can also account for any modifications you might have. After placing your order, please fill out an order sheet for your vehicle (here). Special note when using our core program – GTO’s require a special security relearn that can be done only with a GM Tech 2 scan tool. This is not a issue if you send the PCM out of your car. Please note: automatic LS2 GTO’s will have a separate transmission control module that needs to be sent in when tuning (and/or returned when returning core). If you wish to come to us for a dyno tune after purchasing a mail order tune, we will apply what you’ve paid towards it! What program should I use and what is refundable? Click here!