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Borla 400373 XR-1 Multicore Muffler: 400373. XR-1 Multi-Core Racing Muffler For Rotary Engine Equipped Vehicles - 3 Center Inlet/ 3 Center Outlet 6.25 Round x 16 Long Body 21 Overall Length. Universal Parts. Reversible Design. Along with the distinctive Borla Sound of Power recognized by motoring enthusiasts everywhere, upgrading your ride with a Borla exhaust gives you a boost in power and torque, improved fuel economy, longer engine life and refined motorsport styling. But most of all, Borla gives you the intoxicating rush that comes with every squeeze of the throttle, the thrill of raging power with every shift, and a heart-pounding soundtrack to match. More than anything else, we understand that we build far more than exhaust systems. We build excitement.; Along with the distinctive Borla Sound of Power recognized by motoring enthusiasts everywhere, upgrading your ride with a Borla exhaust gives you a boost in power and torque, improved fuel economy, longer engine life and refined motorsport styling. But most of all, Borla gives you the intoxicating rush that comes with every squeeze of the throttle, the thrill of raging power with every shift, and a heart-pounding soundtrack to match. More than anything else, we understand that we build far more than exhaust systems. We build excitement.
Designed for rotary engine equipped vehicles, but can be used on other applications. Long body is perfect for truck applications. Reversible design for installation flexibility. Patented Multicore design for maximum power. Recommend for high horsepower applications. T-304 Stainless steel will never rust. 100% welded construction for strength. High-temperature continuous-filament fiber (CFF) acoustic material for sound control. There is no logo embossment on this part. Best of all, it's made in the USA. Just what you'd expect from the world's most experienced (and most winning) exhaust brand.- Body Height:6.250 in.
- Body Length:16.000 in.
- Body Width:6.250 in.
- Construction:All Welded
- Grade Type:Performance
- Inlet Connection Type:Pipe
- Inlet Outside Diameter:3.000 in.
- Inlet Position:Center
- Inlet Type:Single Center
- Main Piping Diameter:3.000 in.
- Material:T-304 Stainless Steel
- Muffler Count:1
- Off Road Use Only:No
- Outlet Outside Diameter:3.000 in.
- Outlet Position:Center
- Outlet Type:Single Center Outlet
- Overall Length:21.000 in.
- Shape:Round
- Tip / Outlet Finish:N/A
- Title:XR-1 Multi-Core Racing Muffler 3in Center Inlet/ 3in Center Outlet 6.25in Round x 16in Long Body Rotary Engine Equipped Vehicles
- Title Extended:XR-1 Multi-Core 3in Center-Center 16inx6.25in Round - Rotary Engine Equipped Racing Muffler Part # 400373
BORLA PERFORMANCE INDUSTRIES is the pioneer and leader in the design and manufacture of stainless steel performance exhaust. We began two decades ago as a manufacturer of exhaust systems for such "concours classics" as Rolls-Royce and Ferrari cars and have evolved into the premier manufacturer of today's performance vehicles for the street, off-road, and racing.
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Borla
Discover the Borla Exhaust collection, where world-class exhaust products meet the high standards of automotive enthusiasts. Borla is dedicated to exceeding your expectations by utilizing a state-of-the-art test and development center. This facility allows us to continually refine our manufacturing precision and maintain the highest quality standards. Our commitment to innovation is evident through numerous US patents for advanced exhaust design and multiple "Best New Product" awards in the industry.
Unmatched Customization
What sets Borla apart from other exhaust systems is our vehicle-specific design approach. Each exhaust system is meticulously crafted to accommodate the unique mechanical and acoustical properties of different cars and trucks. We invest countless hours in optimizing various components, such as:
- Muffler body shapes
- Internal core configurations
- Flow dynamics
- Sound characteristics
Exclusive Sound Technologies
Borla offers a choice of three exclusive sound technologies to match your preferences:
- ATAK: Aggressive sound for performance enthusiasts
- S-Type: A blend of performance and refinement
- Touring: A sophisticated sound for everyday driving
With the Borla collection, you can elevate your vehicle's performance and sound, ensuring a driving experience that truly stands out. Choose Borla for unparalleled quality and innovation in exhaust systems.

Exhaust Systems
Welcome to our collection of high-quality exhaust systems, designed to elevate your vehicle's performance while providing an outstanding driving experience. Our website simplifies the search for the perfect exhaust components for your vehicle, allowing you to easily browse through a wide range of custom and performance exhaust parts.
Featured Brands
- AEM
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Why Choose Our Exhaust Systems?
- Improved performance and power output.
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Our user-friendly website enables you to search by make, model, and year, ensuring you find the right components tailored to your vehicle's needs. Explore our selection of top brands:
- Banks Power
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- Borla
- Bosch
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- Stainless Bros
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Mufflers
Welcome to our Mufflers collection, where performance meets style. Our curated selection offers a variety of mufflers to enhance your vehicle’s sound and efficiency. Whether you’re looking for a subtle upgrade or a loud statement piece, we have the perfect options for you.
Why Choose Our Mufflers?
- High-Quality Materials: Crafted from durable materials to ensure longevity and reliability.
- Performance Enhancement: Designed to improve your vehicle’s exhaust flow and overall performance.
- Stylish Designs: Available in various styles to suit your personal taste and vehicle aesthetics.
- Easy Installation: Many of our mufflers come with easy-to-follow installation instructions for a hassle-free upgrade.
Featured Products
Check out some of our top-selling mufflers:
- Performance Muffler X1: Boosts horsepower while providing a deep, aggressive sound.
- Eco-Friendly Muffler Series: Designed to reduce emissions without compromising on performance.
- Customizable Muffler Kit: Personalize your sound and style with adjustable settings.
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Explore our entire range of Mufflers and find the perfect fit for your vehicle. Upgrade your ride today and enjoy a blend of performance and aesthetics!

Mufflers & Resonators
Welcome to our exclusive Mufflers & Resonators collection! We have meticulously curated options to cater to all automotive enthusiasts. Whether you seek to enhance your vehicle's sound, improve performance, or simply replace worn-out parts, you'll find the perfect solutions here.
Why Choose Our Mufflers & Resonators?
- High Quality: Each product is made from durable materials ensuring longevity.
- Enhanced Performance: Our selection is designed to improve exhaust flow for better horsepower.
- Sound Customization: Choose from a variety of sounds to match your style—from aggressive to subtle.
- Easy Installation: Most products come with straightforward installation instructions.
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Explore some of our best-selling Mufflers & Resonators:
- Performance Muffler Series
- High-Flow Resonators
- Universal Muffler Kits
- Custom Exhaust Systems
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We pride ourselves on providing excellent customer service. Our team is here to help you choose the right Mufflers & Resonators for your vehicle. If you have any questions, don’t hesitate to reach out!
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Don’t miss out on upgrading your ride. Browse our Mufflers & Resonators collection today and experience the difference in performance and sound!