Our performance tuning for the 4.2L I6 typically yields 10-14hp and 1-3mpg, as well as better throttle response, driveability, and more pep off the line. Our tuning also helps with towing if you choose to do so. This is included in our core price if ordering the core program. We can account for most modifications you might have (2002-2005 year models: we are not able to make speedometer corrections or remove park/neutral rev limiter). After placing your order, please click on “Ordersheet” and fill out a tuning ordersheet for your vehicle. What program should I use and what is refundable? Click here! Express shipping only covers one shipment for loaner programs, the second will be returned via UPS Ground unless other arrangements are made.