The 15.5-16 GM Duramax is equipped with a diesel particulate filter. DPF removal is the best upgrades you can do to increase fuel mileage and reliability. To properly remove the DPF without codes or setting a checking light you must install a DPF delete capable tuner. Our most popular DPF delete tuner for the 2015.5-2016 Duramax LML is the EZ Lynk. There's two primary things to consider when removing the DPF. Tuning & Exhaust. After you've decided on the DPF delete tuner your next decision is the exhaust system. The most common question we get is 4" vs 5"? If you want a louder exhaust and your trying to squeeze every bit of power install a 5" exhaust system. If you want something slightly louder then stock but not obnoxious go with a 4" exhaust. If you need to install/uninstall the DPF for emission testing or inspection purposes the best way to go about it is a DPF delete pipe. This is a flanged pipe that makes it easy to swap in and out in a relatively short time. In addition, if you'd like to completely remove all emission components you still have the EGR system to contend with. The EZ Lynk tuner also turns off the EGR system. The EGR valve is programmed shut and is de-activated. However you still have the EGR cooler and remaining components. For improved reliability its best to install a EGR delete kit. The EGR delete wont add any power or give you more fuel mileage, its simply to increase reliability. The EGR delete on the LML Duramax is about a 4hr job. If you plan on getting rid of the truck in a year you could probably get away with not deleting the EGR. If your intention is to keep the truck for several years we recommend installing the EGR delete.