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Choosing a Catback Exhaust for 1999-2004 Mustangs

Written By: Stanley Sadowski

Shop '99-'04 Mustang Cat-back Exhaust

Replacing the restrictive cat-back exhaust your stock Mustang came equipped with from the factory will increase horsepower and torque, in addition to completely changing the sound and attitude of your car.

Shop Catbacks

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? When in the market for a new cat-back exhaust you'll want to consider what sound you want, cost, type of muffler, and piping size.

American Muscle

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

Which Mustang Catback Exhaust System Sounds The Best?

Exhaust sound clips for 1999-2004 Mustangs are a great way to hear and select the perfect sound for your Mustang, allowing you to decide what sound is best for your car. There are a lot of components that influence the sound of your exhaust, but the piece that matters most is the mufflers you choose. Each brand has their own signature sound as well as a different style of chambering. These chambers are often filled with a dampening material to remove certain frequencies from your Mustang's exhaust.

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. You'll also get a different sound out of an H-pipe (think more classic Mustang notes) versus an X-Pipe. Tuned length headers, long tubes, and shorties all have unique tones. Consider long tubes for a more dragster sound.

1999-2004 Mustang Cobra with a SLP Loudmouth Cat-Back

How Much Will a '99-'04 Mustang Catback Cost?

Typically, catback systems run between $350 and $800, depending on the brand and overall quality of the steel and structure. 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.

Longevity is also an important facture. A stainless steel exhaust will tolerate the elements for longer than a simple uncoated steel system. If you decide on chrome tips, will you spend the additional cash to keep them looking pristine? A powder coated system (including muffler tips) is an excellent balance between longevity, style, and ease of maintenance.

1998-2004 Mustang GT and Mach 1 Cat-Back System

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.

1979-2004 Mustang Straight Through Style Muffler
Straight Through Style Muffler

What is The Stock 1999-2004 Mustang 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.

Addressing 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.

1999-2004 Mustang V6 Dual Exhaust Conversion Kit
V6 Dual Exhaust Conversion Kit
Fitment includes: 1999, 2000, 2001, 2002, 2003, 2004, gt, v6, cobra, mach1, bullitt