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APR 18-25 Audi S4/S5 (B9) Catback Exhaust System

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$1,827.95
$1,827.95 $2,418.95
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The APR Catback Exhaust System for the Audi B9 S4 and S5 is a complete, high-performance exhaust solution that runs the entire length of the vehicle from the catalyst back. Inspired by the larger center-pipe design of the higher-output RS4 and RS5 models, this system is engineered to boost performance, elevate sound, and enhance aesthetics with customizable exhaust tips that are sure to make a statement. Crafted from premium materials and built with advanced manufacturing techniques, this system is designed to withstand harsh conditions and deliver lasting performance. Expect a bold, aggressive growl at wide-open throttle, along with an impressive gain of 10 horsepower and 12 FT-LBS of torque to all four wheels!

  • Smooth transitions and straight-through components maximize performance by reducing restrictions.
  • Removable quad 3.5” motorsport-style polished tips with APR logo; optional styles available.
  • Complete catalyst-back system including downpipes, extending from the factory catalyst back.
  • Mandrel-bent brushed piping paired with electropolished cast splitters for a refined finish.
  • Precision brackets and slip clamps ensure accurate alignment and hassle-free installation.
  • Premium T304 stainless steel construction with TIG welding for strength and durability.
  • Optimized flow through dual 2.5” downpipes, 2.75” midpipes, and a 3.5” midpipe.
  • Strikes the perfect balance of power, sound, style, and quality for enthusiasts.
  • Performance gains of 10 HP and 12 FT-LBS of torque delivered to all four wheels.
  • Valve-controlled rear mufflers dynamically adjust sound based on driving style.
  • Integrated Helmholtz resonator minimizes drone and enhances sound quality.
  • Includes an upgraded tunnel brace to accommodate the larger piping.
  • Fully emissions compliant for worry-free operation.

This Part Fits:

Year Make Model Submodel
2019-2025 Audi S4 Premium
2018-2025 Audi S4 Premium Plus
2018-2025 Audi S4 Prestige
2019-2024 Audi S5 Premium
2018-2024 Audi S5 Premium Plus
2018-2024 Audi S5 Prestige
2020-2025 Audi S5 Sportback Premium
2018-2025 Audi S5 Sportback Premium Plus
2018-2025 Audi S5 Sportback Prestige

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    Seattle, Washington

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    Austin, Texas

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    Wide variety of products across the range. Found everything I needed in one place, very convenient.

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    London, England

  • Top quality

    The product I bought exceeded my expectations. Top-notch quality, thoughtful design, and it came beautifully packaged.

    Sam Davis
    San Francisco, California

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    Have ordered multiple times, always received exactly what was described. Products are genuine and fully functional.

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    Denver, Colorado

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    Boston, Massachusetts

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    Checkout was quick and straightforward. My order confirmation came through instantly, and everything arrived exactly as expected.

    Morgan Lee
    Portland, Oregon

  • Great value

    Really pleased with the quality for the price. The product felt premium, worked perfectly out of the box, and was well packaged.

    Jamie Carter
    Manchester, England

Can I return a part after it has been installed?

Generally, installed or used performance parts cannot be returned. We strongly recommend verifying vehicle fitment and inspecting the product before installation.

Can I cancel my order after it has been placed?

We begin processing orders as quickly as possible. If you need to cancel, contact us immediately. Once an order has entered fulfillment, been submitted to a supplier, or shipped, cancellation may no longer be possible.

Will this part fit my vehicle?

Fitment varies by year, make, model, trim, engine, and drivetrain. Use our vehicle fitment information to confirm compatibility. If you're unsure, contact us with your VIN and we'll help verify fitment before you order.

How do I know if this is the right upgrade for my build?

Not every upgrade makes sense for every vehicle or build. Tell us your vehicle, current modifications, and performance goals, and we'll help determine whether this product is a good fit.

Are the products you sell authentic?

Yes. We source products through established manufacturers and authorized distribution channels. We do not sell counterfeit or imitation performance parts.

Is professional installation recommended?

For most performance components, yes. Proper installation is critical for fitment, reliability, and performance. Some products may also require specialized tools, programming, tuning, or additional supporting modifications.