If you're talking about the air horn/silencer in the inner fender it's pretty simple to do. Remove your factory style air box from the inner fender and you'll see a black plastic "horn" in the inner fender behind where the air box was mounted. It acts as a funnel for the air box. Remove the nuts that hold it on, reach up from the bottom of the car into the inner fender, and pull it out. Basically it restricts air flow to the engine which theoritically reduces horsepower. Simple enough to do and nothing is better than free horsepower.