5 Best Exhaust For Horsepower Compared (+ Cost & Sound)

By February 6, 2022Exhaust

Seeing multiple aftermarket exhausts in action made me curious about which aftermarket exhaust is best for enhancing a car’s horsepower and how different aftermarket exhausts perform in comparison to one another.

So, let’s dig in.

In no particular order I will specify the various aftermarket exhaust systems that are known to increase a car’s horsepower.

I will discuss these exhausts based on the type, brand, sound, costs, the installation process and discuss whether or not they are legal. 

Most aftermarket exhausts that increase horsepower are Cat-Back types, and they generate a substantial level of noise.


Flowmaster American Thunder  Magnaflow  Cat-Back  Gibson Swept Side Cat-Back  Borla Stainless Steel  MBRP XP Series 
Horsepower Gain 7% 10% 10% 7% 10%
Sound Gain Aggressive & Loud. Deep & Moderate. Deep & Aggressive. Deep & Throaty. Aggressive & Loud
Application Street Street Street Street Racing
Cost $710 $766 $654.99 $640 $709
Installation 2hrs 1hr 1hr 1hr 2hrs
Is It Legal? Yes Yes Yes Yes No

1. Flowmaster American Thunder Exhaust

The Flowmaster American Thunder exhaust produces the roar that the series’ name promises. The exhaust roar of the American Thunder system has become a globally recognized symbol of American power.

American Thunder is the most popular Flowmaster exhaust system, improving power, torque, throttle response, and mileage for car users around the world.

Flowmaster catback

Flowmaster American Thunder Exhaust

Flowmaster American Thunder Exhaust: Horsepower Gain

Flowmaster American Thunder exhaust systems can add roughly 5-7% horsepower increase to your engine.

The amount of performance you gain will be determined by the state of your car and the enhancements you have already installed.

The Flowmaster American Thunder Exhaust system includes 16-gauge mandrel-bent stainless steel tubing that flows into a specially designed Super 40 Series performance muffler with dual 2.50-inch stainless steel tailpipes.

The tailpipes may go behind the rear wheels, which is great for towing, or straight out the back under the rear bumper for a more muscular appearance. A pair of huge 3.00-inch polished stainless steel tips complete the set. 


Flowmaster American Thunder Exhaust: Sound Gain

Flowmaster Exhaust Systems will improve your vehicle’s performance and give it a deep, throaty roar. It’s suitable for off-road trucks.

Here’s a YouTube video showing you the sound from Flowmaster American Thunder Exhaust.


Flowmaster American Thunder Exhaust: Cost

The Flowmaster American Thunder Exhaust costs around $710. You can purchase it online or at known dealer shops. It is also available in Amazon. 


Flowmaster American Thunder Exhaust: Installation

The installation only takes about 2 hours. The American Thunder kit comes with all the hangers and clamps you’ll need for installation. It also comes with detailed instructions on how to install.

The installation depends on your skills. You may need to pay an additional fee to have a mechanic install it for you.


Flowmaster American Thunder Exhaust: Is It Legal?

The Flowmaster American Thunder Exhaust is legal in some states in the US but states laws differ from each other.

Flowmaster has fifteen different styles of performance mufflers allowing customers the opportunity to choose a Flowmaster signature sound ranging from mild to moderate or aggressive to accommodate the customer’s local and state laws.

2. Magnaflow Stainless Cat-Back Exhaust

If you seek improved performance and economy, as well as a powerful and well-tuned exhaust note and is within legal limits with a nice, deep, and manly tone.

The Magnaflow Stainless Cat-Back Exhaust is a suitable option in that circumstance.

The precise free-flow design, top-class craftsmanship, and attention to detail in both design and production all contribute to the power gain.

Magnaflow Stainless Cat-Back Exhaust

Magnaflow Stainless Cat-Back Exhaust: Horsepower Gain

MagnaFlow cat-back exhaust system may improve horsepower by 10%. This depends on the size of your engine and how restrictive your stock exhaust was.

If your engine is big, then the horsepower gain could be larger. Similarly, if your stock exhaust was very restrictive, then switching to an aftermarket like Magnaflow will provide even more horsepower.

Magnaflow exhausts are praised by many custom builders and racers for generating the smoothest and deepest tones on the market, as well as the most significant power gains.


Magnaflow Stainless Cat-Back Exhaust: Sound Gain

The Magnaflow Stainless Cat-Back Exhaust sound is moderate on the exterior and mild in the interior. You and your passengers should not be too annoyed by the sound. 

Magnaflow’s renowned sound is well-known across the automobile industry for its high quality. Here’s a YouTube video showcasing that sound:


Magnaflow Stainless Cat-Back Exhaust: Cost

The Magnaflow Stainless Cat-Back will cost you around $766. You can get it online or at known dealer shops. It is also available on Amazon.


Magnaflow Stainless Cat-Back Exhaust: Installation

Magnaflow Stainless Cat-Back Exhaust System comes with DIY instructions for installation. It can be installed in 1 hour.

They come with everything needed to bolt up in place of your factory system using basic tools. 

Most MagnaFlow products do not require welding, cutting or bending. However, select applications may require additional welding for optimal installation. Typical installations take about 1 hour.

MagnaFlow cat-back exhaust systems include everything from pipes, hangers, clamps, mufflers, and tips to the stainless steel construction. Tips, mufflers, and resonators (where appropriate) are polished stainless steel with a “mirror finish.”


Magnaflow Stainless Cat-Back Exhaust: Legal?

The Magnaflow Stainless Cat-Back exhaust is legal. It complies with the normal emissions standard.

MagnaFlow products are designed and tested to meet legal sound level regulations; but, when combined with additional items (such as air intake systems or exhaust headers), the overall combined impact may cause some vehicles to exceed the acceptable sound limits.

3. Gibson Swept Side Cat-Back Exhaust

The Gibson Side Swept Cat-Back Exhaust is designed to deliver horsepower and torque under real-world driving conditions.

Between 1800 and 3000 rpm, this system delivers the highest horsepower and torque. You get better fuel economy and a good deep, aggressive exhaust tone, as well as more power and performance.

Gibson Swept Side Cat-Back Exhaust

Gibson Swept Side Cat-Back Exhaust: Horsepower Gain

After adding a Gibson Swept Side exhaust, you should expect to gain about 10%. Similar to the Magnaflow, Gibson exhausts are great for horsepower and should give even more depending on your engine size.

Gibson uses optimal tubing diameter for the highest engine efficiency, not the maximum exhaust flow, and then bends every tubing bend with CNC mandrel tube benders.

Mandrel bending guarantees smooth bends and that the pipe retains its size and shape along its entire length. CNC mandrel bending ensures uniform bending, ensuring that every system operates as intended.


Gibson Swept Side Cat-Back Exhaust: Sound Gain

The Gibson Swept Side Cat-Back Exhaust gives off a very deep and aggressive exhaust tone – more suitable for off-roading purposes. 

There is no packing to blow out because the enhanced flow and superb sound are accomplished without muffler packing. Throughout the life of the muffler, the exhaust flow and sound will stay consistent.

Here’s a YouTube video showcasing the sound from Gibson Swept Side Cat-Back Exhaust:


Gibson Swept Side Cat-Back Exhaust: Cost

The Gibson Swept Side exhaust will cost you around $654.99. You can order it from car workshops or buy from any authorized dealer to avoid rip-offs. It is also available on Amazon. 

Gibson is now one of the world’s largest manufacturers of aftermarket performance exhaust products. 

Gibson is committed to creating low-cost exhaust systems that provide more performance and generate more horsepower and torque in the lower rpm range, where it is needed for real-world experience.


Gibson Swept Side Cat-Back Exhaust: Installation

Everything needed for installation is included, including zinc-plated factory style hangers and clamps as well as full instructions.

You could refer to the YouTube video I showed above. That also shows you how the installation is done. 


Gibson Swept Side Cat-Back Exhaust: Legal?

Gibson Side Swept Cat-Back Exhaust All of Gibson’s street applications are 50-state emissions legal and do not affect the factory warranty

Check with the seller, especially when it comes to sound. California is the strictest state in the US, only allows vehicles to produce sound up to 95 dB.

4. Borla Stainless Steel Cat-Back Exhaust

The Borla Stainless Steel Cat-Back is a fantastic choice for increasing horsepower while decreasing fuel consumption

Borla Cat-back and Rear Section exhaust systems utilize unique straight-through and multi-core technology to unleash hidden horsepower.

Borla Stainless Steel Cat-Back Exhaust

Borla Stainless Steel Exhaust: Horsepower Gain

You will gain 8 to 12 horsepower increase (roughly 7%), and in some cases much higher

The innovative straight-through, multi-core muffler design helps to eliminate blockage. It enhances the speed of the exhaust gas, ensuring that each cylinder is entirely cleared to allow the incoming charge.

Three decades ago, the company began creating exhaust systems for classic Rolls Royce and Ferrari cars and eventually grew to become the leading manufacturer of performance exhaust solutions for street, off-road, and racing.


Borla Stainless Steel Exhaust: Sound Gain

The Borla Catback exhaust gives a loud and very throaty sound (Even louder during cold start). If you are a person who gets annoyed by sound, then the Borla may not be the best choice.

The exhaust sound can be heard from the interior – especially when you accelerate. This exhaust is suitable for those who like aggressive exhaust sound that can attract eyeballs.

Here’s a YouTube video showcasing the sound from Borla Catback exhaust:


Borla Stainless Steel Exhaust: Cost

The cost of a Borla Stainless Steel Cat-Back is around $64. The Bola Stainless Steel Cat-Back exhaust is available on Amazon. and purchased at any online store or dealership.

Each Borla exhaust is made using the finest materials and construction techniques to ensure this won’t happen. To resist corrosion, they use austenitic stainless steel for their systems, which contains high levels of nickel and chromium.


Borla Stainless Steel Cat-Back Exhaust: Installation

Borla Stainless Steel Cat-Back Exhaust System includes everything needed for installation, including step-by-step instructions. Installation process could take up to an hour.


Borla Stainless Steel Cat-Back Exhaust: Legal?

The Borla stainless steel Cat-back exhaust is street legal. Borla street Cat-Backs, Rear Sections, and Mufflers are all 50-state emissions compliant. These systems have no effect on your manufacturer warranty.

5. MBRP XP Series Exhaust

The XP Series from MBRP is the performance exhaust of choice for you if you are looking for a system that can withstand whatever the road throws at you

The sturdy 16 gauge T409 build of this system is designed to withstand the harshest road conditions.

MBRP XP Series Exhaust

MBRP XP Series Exhaust: Horsepower Gain

Performance increase may vary depending on the vehicle, you may expect a 5%-10% increase in horsepower and torque.

The MBRP XP Series exhaust system will provide the least amount of backpressure, allowing all of your other engine modifications to produce maximum horsepower.

It is only for competition or racing purposes because it removes the factory catalytic converter.

When it comes to performance exhaust technology for race vehicles, MBRP Inc. is currently the best. with a breakthrough in the development of new sport line components for gasoline-powered cars.


MBRP XP Series Exhaust: Sound Gain

The MBRP XP Series Exhaust creates a deep mellow exhaust note that MBRP Inc. systems are known for. 

Here’s a YouTube video showcasing the sound from MBRP XP Series exhaust:


MBRP XP Series Exhaust: Cost

The MBRP XP Series Exhaust could cost around $709. You can purchase the MBRP XP Series exhaust from Amazon or from any known dealer.

The XP series is engineered and manufactured to withstand the roughest road conditions. T409 will rust on the surface over time, but never through.


MBRP XP Series Exhaust: Installation

MBRP XP Series Installation may take up to 2 hours

Installation is simplified by well-engineered bolt-on over the original bearings, which are backed up by detailed user manuals and a toll-free technical support line to assist even the most inexperienced installer. 


MBRP XP Series Exhaust: Legal?

MBRP XP Series exhaust is not street legal. It is mostly for race or sport use only. 

It exists solely for the sake of competing. It is not allowed to be used on vehicles operated on public streets, roads, or highways

It is only applicable to closed-course and open-course racing that is properly sanctioned by recognized racing organizations.

Which Exhaust Should You Install?

Personally I would recommend the Flowmaster American Thunder Exhaust system because of its unique sound. It is widely used in the US, and it has gained so much  popularity it is now seen as a symbol of American power.

The unique Delta Flow and the Laminar Flow technologies are used in Flowmaster exhaust systems. They produce a variety of sound characteristics and can be modified to produce the appropriate exhaust note.

When choosing your exhaust system, the model and specific features of your car are very important as they determine the type of exhaust system that is compatible with your car.

 To choose the best exhaust system for your car, I have specified the factors to consider when choosing an exhaust system for your car.


Exhaust for Large Trucks and SUVs

The Gibson Swept Side exhaust is an ideal exhaust for trucks and SUVs. It is very efficient when used for towing purposes. It’s sound fits well with the identity of Trucks and SUVs.

It  produces a deep and throaty sound and improves performance and horsepower.

The exhaust system uses optimal tubing diameter for the highest engine efficiency, not the maximum exhaust flow, and then bends every tubing bend with CNC mandrel tube benders.

For Race Cars

If you are looking for an exhaust to boost the horsepower of a race car I would suggest you buy the MBRP XP Series exhaust.

You can use it on the racetrack. However, it is street illegal due to its loud noise.

The MBRP XP Series exhaust is custom built for races, it’s sound is very loud and aggressive being a turbo-back type of exhaust.

It has a rugged exhaust system that delivers exceptional torque, horsepower and performance. 

Ifandi L.

Ifandi L.

Passionate about everything mechanical. Ifandi has been involved with motorcycles and cars since the old days - in his family's auto parts shop. Want to keep in touch? Scream "STRAIGHT PIPEEEEE" at the top of your lungs and Ifandi will show up.

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