Our performance tuning for the 2008-2009 G8 typically yields 15-20hp. Our GTs and GXPs usually pick up 25-30hp 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. If you have a six speed auto transmission, the T43 controller is part of the transmission, and will not be able to sent in for tuning (we can tune it in person or with HP tuners). After placing your order, please fill out an order sheet for your vehicle (here). What program should I use and what is refundable? Click here!