Upgrade your stock B58 downpipe to the MAD B58 Catted Downpipe for more power, better sound, and guaranteed reliability without triggering a check engine light.

The MAD Catted B58 Downpipe is the ideal performance upgrade for BMW owners who want more out of their car without the hassle. It's made from premium 304 stainless steel and built to handle extreme heat and tough driving conditions.

The smooth piping design allows for maximum exhaust flow, which translates into more horsepower, better torque, and sharper throttle response. The 300-cell high-flow catalytic converter gives you noticeable gains and a more aggressive sound, all while keeping the check engine light off.

Installation is simple with a direct bolt-on fit to the stock exhaust system. No cutting or welding needed. It's also fully compatible with most aftermarket exhaust setups, giving you the flexibility to build the setup you want.

No check engine light guarantee
If you get a CEL related to the catalytic converter, MAD will replace the downpipe for free.

Warranty coverage

• 1-year warranty on the catalytic converter

• Lifetime warranty on the downpipe for defects and fitment

Race use only

Features

• No CEL guarantee or it's replaced free

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

• Smooth bends for maximum airflow without drone

• Gains up to 30 horsepower on stock turbos and even more with upgraded ones

• Lifetime warranty on the downpipe

• 1-year warranty on the catalytic converter

• Ships in 1 to 2 business days

• Direct bolt-on fitment

• Flex section for durability

• 300 cell high-flow catalytic converter

Fitment

• 2015 and up BMW M240i and XDrive

• 2016 to 2019 BMW 340i and XDrive

• 2020 to 2024 BMW M340i and XDrive (does not fit 2025+)

• 2016 and up BMW 440i and XDrive

• 2016 and up BMW 540i and XDrive

• 2016 and up BMW 740i and XDrive

• 2017 to 2020 BMW X3 M40

• 2017 to 2020 BMW X4 M40

• 2019 and up G05 BMW X5 40i and XDrive

• 2019 and up G07 BMW X7 40i and XDrive

• 2019 and up G29 BMW Z4 M40i

• 2019 and up Toyota Supra 3.0L

Disclaimer
For race use only. This product is not certified for use on public roads and may not comply with local regulations. Always check your local laws before installing.