aFe Large Bore HD 4in 409 SS Cat Back Exhaust w o Tip Dodge 03 04 (49 12005). Large Bore HD Aluminized Steel Cat Back Exhaust System with Single Side Exit (49 12005) by aFe. Exhaust System Type: Cat Back. Exhaust Tubing Material: Aluminized Steel. Main Tubing Diameter: 4". Exhaust System Sound: Aggressive Loud. Get increased exhaust flow, more horsepower and torque, improved performance and lower exhaust gas temperatures with the aFe Large Bore HD Cat Back Exhaust System. aFe dyno tests every system for maximum gains, and constructs them from mandrel bent stainless steel for maximum flow and long lasting durability. A performance exhaust system is one of the most common ways of improving a vehicle's operation. The theory is simple; just reduce restriction to increase exhaust flow and you gain power. But all exhaust systems are not created equal; in reality there's more to it than just selling some sewer pipe sized tubes. aFe tests its systems on the flow bench and the dynamometer to determine the right pipe size and muffler construction. Then they mandrel bend the pipes to ensure they maintain their shape and size throughout the entire length, to provide smooth, unrestricted airflow. Tubes that are not mandrel bent can lose up to 20% of their diameter in sharp bends. An 8" diameter by 30" length, straight, flow through, perforated muffler is included in the system. A straight muffler delete pipe is also included if a more aggressive sound and maximum flow is desired. This system will increase exhaust flow by up to 29% and lower EGT (Exhaust Gas Temperature) by up to 100 , with a corresponding improvement in power and performance. But performance is only part of the equation. A quality exhaust system should be easy to install and made to last. The muffler and all pipes of the Large Bore HD system are constructed from durable 409 stainless steel. To ensure a tight seal, slotted and swedged ends are used whenever possible. When used with the supplied premium quality band clamps, the tightest, leak free seal is the result. Every hanger is thoroughly welded on each side to ensure a strong attachment and the hangers also feature swaged bayonet ends to lock in place once installed. The factory mounting locations are used throughout and a 2 piece tailpipe facilitates adjustment. Every system comes with clamps, hangers and detailed instructions to guide you through the installation. The Large Bore HD Exhaust System is made in USA. aFe (Advanced Flow Engineering, Inc.) manufactures performance products for late model cars, light trucks and SUVs. The company was founded in 1999 with an initial concentration on high performance air filters. Since then, the company product line has broadened to include cold air intakes, fluid filters, exhaust systems, intake manifolds, intercoolers, programmers, differential covers, transmission pans and throttle body spacers. The team of engineers, machinists, production and sales people at aFe have many years of experience in their respective positions, and together work to ensure they produce the best automotive products on the market. Features: 4 in. Mandrel Bent 409 Stainless Steel Tubing Maximum Flow High Flow Muffler Lower EGTs Bayonet Style Hangers For Easy Installation Increased Horsepower And Torque 2 Year Limited Warranty