Choosing a Catback Exhaust for 1999-2004 Mustangs

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Picking out a new cat-back system for your 1999-2004 Mustang can be quite the task. After all, they all look the same, right? How do you know which one is right for you? When in the market for a new cat-back exhaust some things you want you consider is what kind of sound you expect out of the exhaust, how much money you are looking to spend, which type of muffler you want, piping size, and correct fitment for your year and model.

Keys to Choosing a Catback Exhaust for 1999-2004 Mustangs

  • • Mufflers are the most important influence on your Mustang’s exhaust sound

  • • Deciding how much money you are willing to spend is a key step in choosing your new catback system

  • • There are two styles of mufflers: chambered and straight-through

  • • Most aftermarket catback systems are 2.5 inches in diameter all the way through, ideal for most reasonable street and track builds

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Which Mustang Catback Exhaust System Sounds The Best?

There are a lot of components that can influence the sound of your exhaust, but the piece that matters most is the mufflers you choose. Your headers and mid pipe also directly affect the sound of your exhaust note. If you are running an off-road mid pipe then keep in mind how much louder and possibly raspier the exhaust note may be with the cat-back you choose. Exhaust sound clips for 1999-2004 Mustangs are a great way to hear and select the perfect sound for your Mustang.

Catbacks & Your Budget

The most important step is figuring out how much money you are looking to spend on your new cat-back system. The type of muffler, quality of steel used, style of exhaust tip used, and the reputation of the brand are all things that affect the price of a unit. Decide which features mean the most to you.

Complete Aftermarket 99-04 Exhaust

Mustang Catback Muffler Styles

There are two different styles of mufflers available for your Mustang: There are chambered and straight-through mufflers—also known as resonators. What’s the difference? Chambered mufflers route the exhaust gas through a series of compartments or “chambers.” The more chambers there are inside the muffler, the quieter and mellower the exhaust note will be. Straight-through style mufflers route the exhaust gas straight through the center of the muffler which offers the loudest and most aggressive sound. Be prepared to announce your presence well before anyone sees you coming.

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Exhaust Piping Size

The factory cat-back exhaust piping is 2.5 inches and is reduced to 2.25 inches on most setups. Many aftermarket cat-back systems are all 2.5 inches all the way through. The diameter of the piping affects how much back pressure will be generated. Most aftermarket systems are available with 3.5 inch exhaust tips and some kits feature a 4 inch exhaust tip which offers an even more aggressive look.

1999-2004 Mustang Catback Fitment

Most cat-back systems all fit about the same. They are designed to follow the factory exhaust route but are tucked up a little to assure proper clearance. When purchasing a new cat-back system be sure the unit you have selected pertains to your year and model of Mustang you own. Most exhaust setups are fit for each body style. For example, on SN-95 Mustangs there are different exhaust setups for 94-95 models while some fit 94-97, and others only fit 98’s.


Be cautious between the differences of V6, GT, and Cobra cat-backs. Most aftermarket six cylinder cat-backs start as one pipe and split into two for dual exhaust out of the rear of the car. Mustang GT exhausts are designed to go over the rear axle of the car because they are equipped with solid rear axles. Cobras are equipped with IRS, or independent rear suspension, in the 99-04 model years and their cat-back systems are designed to go underneath the center of the rear and around the gas tank to exit out the rear of the vehicle.

FItment includes:   •   1999, 2000, 2001, 2002, 2003, 2004, GT, V6, Mach 1, Bullitt, Cobra Mustangs

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