MAD BMW F & G Chassis 5" B58 Catted Downpipe M240 340 M340 440 M440 540 W/ No CEL Guarantee & Bracket

Upgrade your BMW’s performance and sound with the MAD 5" Catted Downpipe, engineered specifically for B58-powered BMW F and G chassis models. This high-performance downpipe delivers increased horsepower, improved throttle response, and a deeper, more aggressive exhaust note—all without triggering a check engine light.

Crafted from race-grade 304 stainless steel, the downpipe features a smooth, mandrel-bent 5" design for maximum flow. A 300-cell high-flow catalytic converter is integrated to maintain efficient emissions performance while optimizing exhaust velocity. The result is a significant performance increase with a refined tone that enhances the driving experience.

This system is designed as a true bolt-on upgrade with no cutting or welding required. It fits directly to your factory or most aftermarket exhaust systems and includes a built-in flex section to reduce stress and ensure long-term durability.

Key Features

• No check engine light (CEL) guarantee. If CEL appears due to the cat, MAD will replace the downpipe free of charge

• 300-cell high-flow catalytic converter for increased power and cleaner emissions

• Large 5" diameter piping with mandrel bends for optimal airflow

• Made from 304 stainless steel with precision TIG welds

• Integrated flex section for enhanced reliability and vibration resistance

• Direct bolt-on fitment to OEM and most aftermarket exhaust systems

• Gains up to 30 horsepower on stock turbos, with greater gains possible on tuned setups

• Compatible with both right-hand drive and left-hand drive vehicles

• Lifetime warranty on the downpipe body and 1-year warranty on the catalytic converter

• 90-day return policy

• Ships within 1–2 business days

Vehicle Fitment

Compatible with the following B58-powered models:

BMW

• M240i / xDrive (2015 and up)

• 340i / xDrive (2016–2019)

• M340i / xDrive (2020–2024)

• 440i / xDrive (2016 and up)

• M440i / xDrive (2020 and up)

• 540i / xDrive (2016 and up)

• 740i / xDrive (2016 and up)

• X3 M40i (2017–2020)

• X4 M40i (2017–2020)

• X5 40i / xDrive (2019 and up)

• X7 40i / xDrive (2019 and up)

• Z4 M40i (2019 and up)

Toyota

• GR Supra 3.0L (2019 and up)

Important Note

This product is intended for race use only. It is not certified for road use and may not comply with local emissions regulations. Please consult your local laws prior to installation.