Catless Turbo 3" to 2.5" Downpipe Exhaust for 1997-2005 Audi S4 B5 A6 Allroad C5 2.7L K03 K04 RS6

SKU: XKV21074
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Fitment & Specs
Fits selected Audi 2.7L V6 30V turbo manual-transmission applications, including 2000–2002 S4 / RS4 B5, 2000–2004 A6 Quattro C5, and 2001–2005 Allroad Quattro. Compatible with K03, K04, and RS6 turbo setups. Verify model year, chassis, transmission, turbo setup, and exhaust compatibility before purchase.
3" Inlet · 2.25" Outlet
T304 Stainless Steel · Catless Turbo Downpipe
Before You Buy: Off-road/racing use only · Professional install recommended · Tuning may be required
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Description

This catless turbo downpipe set is designed for listed Audi 2.7L B5 / C5 V6 30V turbo applications, including compatible S4, RS4, A6 Quattro, and Allroad Quattro models. It is intended for compatible K03, K04, or RS6-style turbo setups where the listed flange and exhaust configuration match the vehicle.

Built from T304 stainless steel with mandrel-bent 3" to 2.5" piping, flex sections, V-band style connections, and CNC-machined flanges as listed, this downpipe set is designed as a catless race-style exhaust component. Final fitment, sound, turbo response, drivability, and performance results may vary depending on vehicle condition, turbo setup, transmission, O2 sensor configuration, installation quality, tuning, and supporting modifications.

Product Overview

This product is a catless turbo downpipe set for compatible Audi 2.7L twin-turbo applications. It is not a header set, full exhaust system, catback system, or universal pipe kit. Please verify your exact model, engine, transmission, turbo setup, flange connection, O2 sensor layout, and emissions requirements before purchase.

Key Details

  • Fitment: Listed Audi B5 / C5 2.7L V6 30V turbo applications
  • Product Type: Catless Turbo Downpipe Exhaust Set
  • Turbo Fitment: K03 turbo and upgraded K04 / RS6-style turbo setups as listed
  • Transmission: Manual transmission only as listed
  • Material: T304 Stainless Steel as listed
  • Pipe Design: 3" tapering to 2.5" as listed
  • Inlet / Outlet: 3" inlet / 2.25" outlet as listed
  • Wall Thickness: 16-gauge / 1.5mm as listed
  • Design: Catless downpipe configuration with flex sections as listed
  • Connection: Hybrid inlet flange design for compatible K03 / K04 / RS6 turbo setups as listed
  • Installation: Professional installation recommended
  • Use Case: Off-road, racing, or closed-course use where emissions laws apply

Fitment

Please use the table below to quickly confirm the main vehicle applications listed for this downpipe set. Before ordering, verify your exact model year, engine, transmission, turbo setup, flange connection, O2 sensor layout, and exhaust configuration.

Vehicle Name Year Engine Notes
Audi S4 B5 2000–2002 2.7L V6 30V Turbo Manual transmission only; verify turbo setup and O2 sensor layout
Audi RS4 B5 2002 2.7L V6 30V Turbo Page-listed fitment; verify turbo setup and exhaust configuration
Audi A6 Quattro C5 2000–2004 2.7L V6 30V Turbo Manual transmission only; verify turbo setup and exhaust configuration
Audi Allroad Quattro C5 2001–2005 2.7L V6 30V Turbo Manual transmission only; verify turbo setup and exhaust configuration
Fitment Note: This table is based on the fitment information currently listed for this product. This downpipe set is for listed 2.7L B5 / C5 V6 30V turbo models only and is listed for manual transmissions only. Please verify your exact vehicle, transmission, K03 / K04 / RS6 turbo setup, flange connection, O2 sensor layout, and exhaust configuration before purchase.

Package Includes

  • Catless turbo downpipe components as shown
  • Flex pipe sections as listed
  • V-band clamps / flanges included as shown or listed
  • Hardware included only if shown or listed

Please review the product photos and listing details before installation. Confirm all included components, clamps, flanges, gaskets, sensors, and hardware requirements against the received package before beginning installation.

Installation Notes

  • Professional installation is strongly recommended.
  • Test fit all components before final tightening.
  • Verify turbo flange fitment, V-band connection, sleeve clamp connection, O2 sensor location, and exhaust alignment before installation.
  • Check clearance around the turbocharger area, transmission, driveshaft, heat shields, subframe, underbody, and surrounding exhaust components.
  • Some vehicles or modified turbo setups may require adjustment, supporting exhaust components, or fabrication.
  • Compatible tuning or calibration may be required depending on O2 sensor configuration and emissions setup.
  • Inspect all connections for exhaust leaks after installation and recheck clamps / fasteners after initial heat cycles where appropriate.

Before You Buy

  • This product is intended for listed Audi 2.7L B5 / C5 V6 30V turbo applications only.
  • This listing is for a catless turbo downpipe set, not a header set, full exhaust system, catback system, or universal pipe kit.
  • This product is listed for manual transmission applications only.
  • This product may alter or remove catalytic converter / emissions-related exhaust components depending on the vehicle setup.
  • This product is intended for off-road, racing, or closed-course use where emissions laws apply.
  • This product is not represented as street legal, emissions-compliant, CARB-compliant, or legal for public road use unless explicitly stated.
  • Please verify local regulations, turbo setup, O2 sensor layout, flange connection, exhaust layout, and tuning requirements before purchase.
  • Performance gains, turbo response, sound changes, exhaust flow changes, fitment, and drivability results are not guaranteed and may vary by setup.
Shipping & Return

SHIPPING & DELIVERY
Fast Processing & Reliable Transit

  • Processing: Orders are processed and shipped from the nearest available warehouse within 1 business day after payment.
  • Delivery: Estimated delivery time is approximately 3–4 business days after shipment.
  • Shipping - Free shipping on all orders within the contiguous 48 U.S. states.

RETURNS & EXCHANGES
30-Day Hassle-Free Policy

  • Return Window: We offer a 30-day return policy from the date of delivery.
  • Item Condition: Returned items should be unused, uninstalled, and in their original packaging when possible.
  • Return Process: To initiate a return or exchange, please contact our customer service team first to receive authorization and instructions.

WARRANTY
2-Year Limited Replacement Warranty

  • Duration: All products are backed by a 2-year limited warranty.
  • Coverage: This warranty covers manufacturing defects and product failures under normal use, and provides a replacement for qualified cases (repairs are not performed).

CUSTOMER SUPPORT
We’re Here to Help – Contact Us First

  • Priority Contact: For any order-related issues—including returns, warranty claims, or general inquiries—please contact us first before taking further action. We are committed to resolving your concern promptly.
  • Feedback Notice: If you are unsatisfied, we kindly ask that you allow us an opportunity to address the issue before leaving neutral or negative feedback.
  • Email Support: You can reach us at support@XKVracing.com.

Downpipe Buying Guide

A Key Section in a Turbocharged Exhaust System

The downpipe connects directly to the turbocharger and routes exhaust gases into the rest of the exhaust system. It is one of the first exhaust components downstream of the turbo.

Because of its position, the design of the downpipe influences how exhaust gases move away from the turbo and into the remaining exhaust path.

What Drivers May Observe

More consistent exhaust flow downstream of the turbocharger

Reduced restriction compared to some factory exhaust layouts

Smoother boost delivery under certain operating conditions

Changes in exhaust tone, depending on system setup

Catted vs Catless

Catted Downpipe

Includes a catalytic converter designed for specific applications
Used where emissions considerations or regulations apply
Often selected for vehicles intended for street use, where permitted

Catless Downpipe

Does not include a catalytic converter
Typically intended for off-road, competition, or export use
Used in applications where different regulatory standards apply

Is a Downpipe Right for Your Build?

Own a turbocharged vehicle

Are upgrading intake, intercooler, or exhaust components

Want improved exhaust efficiency and response

Are building a balanced street or track setup

FAST SHIPPING

Ships within 1 business day after payment
3–4 business day delivery

Secure and Reliable Checkout

Secure checkout with major payment options

LOCAL WAREHOUSE

Orders ship from U.S. warehouses when available

Easy Returns and Exchanges

30-day returns for eligible unused items

Parts Warranty

Warranty support for qualified manufacturing defects

Important Notice

Products on this site are intended for off-road, racing, or closed-course use where emissions laws apply. They are not represented as street legal, emissions-compliant, or legal for use on public roads unless explicitly stated.

Some products may remove, replace, relocate, disable, or alter emissions-related components, including but not limited to catalytic converters, EGR, DPF, SCR, DOC, O2 sensors, or related factory systems. Compatible tuning, calibration, or supporting modifications may be required to avoid engine codes or drivability issues.

Professional installation is recommended. Buyers are responsible for verifying product compatibility, local regulations, emissions requirements, and any required tuning or supporting modifications before purchase and installation.

Performance gains, sound changes, airflow improvements, temperature changes, fuel economy changes, fitment, and drivability results may vary. No specific performance gains are guaranteed.

Downpipe FAQs

What is a downpipe? +

A downpipe is the exhaust section that connects to the turbocharger and routes exhaust gases toward the rest of the exhaust system. Depending on the vehicle and product design, an upgraded downpipe may help reduce exhaust restriction and support improved turbo response when paired with the right setup.

What's the difference between catted and catless downpipes? +

A catted downpipe includes a catalytic converter, while a catless or racing downpipe does not include one and may alter or remove emissions-related equipment. Catless or racing downpipes are generally intended for off-road, racing, or closed-course use where emissions laws apply. Always check the product details and local regulations before purchase.

Will a downpipe increase horsepower? +

A downpipe may support improved exhaust flow and power potential when combined with proper tuning and supporting modifications. Horsepower and torque gains are not guaranteed and will vary depending on the vehicle, engine condition, tune, fuel, turbo setup, and overall exhaust system.

Do downpipes make the vehicle louder? +

A downpipe can change exhaust tone and may increase turbo or exhaust sound depending on the vehicle, whether the downpipe is catted or catless, and the rest of the exhaust system. Final sound level varies by setup.

Do I need tuning after installing a downpipe? +

Tuning requirements depend on the vehicle, downpipe design, emissions equipment, O2 sensor setup, and supporting modifications. Some applications may require compatible tuning or calibration to support drivability and reduce the chance of warning lights or engine codes.

Will a downpipe trigger a check engine light? +

It may, depending on the vehicle, catalytic converter configuration, O2 sensor location, and ECU calibration. Catless or racing downpipes are more likely to require supporting calibration or sensor-related solutions. Always verify the product notes and tuning requirements before installation.

Are downpipes street legal? +

Street legality depends on the downpipe design, emissions equipment, vehicle application, and local regulations. Catless, racing, or emissions-altering downpipes are generally intended for off-road, racing, or closed-course use where emissions laws apply and are not represented as street legal unless explicitly stated.

Can I use a downpipe with my stock exhaust system? +

Compatibility with a stock exhaust system depends on the vehicle and the specific downpipe design. Some downpipes are designed to connect to factory-style exhaust sections, while others may require compatible aftermarket exhaust parts, adapters, clamps, gaskets, or fabrication. Always check the product fitment and installation notes before ordering.

Are downpipes hard to install? +

Installation difficulty varies by vehicle. Some applications require tight access around the turbocharger, O2 sensors, heat shields, transmission area, or underbody. Rusted factory hardware and limited clearance can also increase installation difficulty. Professional installation is recommended.

Will a downpipe affect reliability? +

Reliability depends on product fitment, installation quality, tuning or calibration, heat management, sensor placement, gasket sealing, fastener condition, and the vehicle’s overall condition. Incorrect installation or mismatched tuning may cause drivability issues.

What should I verify before buying a downpipe? +

Verify your year, make, model, engine, turbo setup, emissions configuration, catalytic converter requirements, O2 sensor layout, flange or clamp connection, exhaust compatibility, and any tuning or calibration needs before purchase.