The 2003 Ford 6.0 Powerstroke engines brought a change to the Ford PCM which would not accept a plug in chip like the 7.3 before it took. Instead all computer adjustments have to be done by "flashing" the PCM. We carry a for range of products that will reprogram your 6.0 Powerstroke for better fuel economy and more horsepower. Most programmers will add roughly 100 horsepower at the rear wheels on their highest settings. More power is available from the stock injectors with custom tuning on a programmer like the SCT. If you are having troubles figuring out which programmer would be the best one for you application, please feel free to give us a call. We would be glad to help!