You have to buy a tuner (if you can still get) I went with a Smarty Jr and you have to remove everything at the same time. DPF, EGR Cooler and install the tuner. I did away with the cat, dpr, egr cooler, and the piece on the intake. Turbo back exhaust w/muffler. Did the work myself, the whole 9ydrs was about $1,009.00. the truck will get 22mpg @65mph.