Enhance your 6.6L Duramax's power potential by installing any of our featured aftermarket Chips, modules and tuners! Give your Cateye additional horsepower, torque and throttle by upgrading your stock PCM with a performance-oriented tuner! With our carefully chosen line of tuners for your LLY, you'll be able to choose how and when your truck makes power, for towing ands hauling, for economy, and daily driving. You'll also improve shifting for enhanced gear-holding and optimized shift pressures, GM 2500HD/3500HD owners can expect an excellent increase in overall performance. Achieve improved injection timing/pulse and fuel rail pressure with a new aftermarket PCM Tuner from Alligator Performance. For even greater added power, check out our selection of Turbo Upgrades.GM Duramax Fitments: 2004, 2005 GM 6.6L Duramax.Submodel Fitments: WT, Custom, LT, LTZ, High Country, 1LT, 2LT, Pro, SLE, SLT, AT4, Denali.Some exceptions apply, please see individual product pages for specific fitments.