Aftermarket tuning can give your diesel truck absolutely huge levels of horsepower and torque, but few devices give you shift-on-the-fly tuning in a convenient package. These Stealth Performance Modules are compact, easy-to-use tuning modules that can add extreme power to your tough truck in practically no time. Stealth's tuning modules come with plug-and-play connectors that hook right into your truck's ECM system and include a knob for changing power levels on the fly. Stealth has Duramax tuning modules, Cummins tuning modules, and Powerstroke tuning modules available for basically any model year so that you can get hassle-free performance gains for your tough diesel truck of choice.