The factory exhaust system does its job, but it's not overly efficient and prevents your truck from generating the horsepower, torque, and sound that your 6.0L Powerstroke V8 is capable of. All of the 6.0L exhaust systems available here at Stage 3 greatly reduce the amount of back pressure in your 2004 to 2007 Super Duty's exhaust system and are capable of adding up to 15 horsepower and 25 lb-ft of torque. Our premium exhaust kits also help lower EGTs and can allow you to run mid-level PCM tuning for even better horsepower and torque gains. Ford Super Duty Fitments: 2004, 2005, 2006, 2007 Ford F250 & F350 6.0L Submodel Fitments: FX4, King Ranch, Platinum, Lariat, XLT, XL Some Exceptions apply, please see individual product pages for specific fitments.