Magnum Force Stage 2 Si Intake System (54-81174) by aFe. Filter Series: Pro 5R. HP Gain: +19 hp. TQ Gain: +27 lbs. x ft.. Includes: Air Filter, Sealed Roto-Molded Housing with Auxiliary AirScoop, Black Aluminium Cover, Dyno Tuned Tube. The aFe Stage 2 Si Cold Air Intake System replaces your entire factory air intake system with a large high-flow aFe air filter, a totally enclosed airbox and a smoothly contoured, less restrictive intake tube. This system enables your engine to take in huge quantities of dense, cool, oxygen laden air. The result is better combustion, increased horsepower and torque, and a noticeable gain in performance.