This SFR exhaust uses two HKS mufflers for the ultimate in flow and sound .All of these true dual exhaust systems come in three sections per side.This makes shipping cheaper and the installation easier. We provide high quality gaskets and stainless hardware for a leak free seal. This is a true dual system which bolts up to your stock catylists, test pipes or your Speed Force Racing twin-turbo down pipes. We recommend the 2.5" systems for N/A cars that want to make the most horsepower and torque possible. For turbo cars, we suggest the dual 3" system.This will allow the turbochargers to make the most power possible. We guarantee it! These systems were designed for the stock rear bumper. Aftermarket bumpers might require slight modification.