2004.5-2005 GM Duramax 6.6L LLY Downpipes

Replacing the restrictive factory downpipes on your 2004.5-2005 GM 6.6L Duramax LLY build is a great way to improve both the power and performance of your Sierra/Silverado. These aftermarket downpipes work to give your truck an awesome sound while improving it's power, torque, and fuel economy along the way. These kits will even help slightly drop EGTs to help maintain controllable temperatures on your truck without compromise. Choose from the entire selection of downpipes to get the exact look and sound your tough GM truck deserves, and start showing off your performance mods with confidence. 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.