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

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

• The "No CEL" guarantee is valid for 2 years from the date of purchase.

• The lifetime warranty still applies in cases of manufacturer defects, such as cracks in the pipe or welds.

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

• 2-year warranty on the catalytic converter

• Direct bolt-on fitment

• Flex section for durability

• 300 cell high-flow catalytic converter

NOTE: Downpipe gasket is not included. Part #18328612538 is required for installation.

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

• 2016-2020 640 GT & X drive G32

• 2016 and up BMW 740i and XDrive

• 2017-2024 X3 M40 G01/G02

• 2017-2024 X4 M40 G01/G02

• 2019-2022 G05 BMW X5 40i & xDrive Non LCI only

• 2018-2022 G06 X6 40I & x drive Non LCI only

• 2019+ G07 BMW X7 40i & xDrive Non LCI only

• 2019 and up G29 BMW Z4 M40i

• 2019 and up Toyota Supra 3.0L

Emissions Disclaimer:
This product is not legal for sale or use on pollution-controlled vehicles operated on public roads, highways, or streets. It is intended for off-road, race, or closed-course competition use only, where such modifications are permitted.

By purchasing this product, you acknowledge and agree that:

• You are responsible for compliance with all applicable emissions laws and regulations.

• MAD and its affiliates disclaim any liability for improper or unlawful use of this product.

• Use of this part on public roads may violate the Federal Clean Air Act (42 U.S.C. § 7522) and similar state laws.

Please check your local laws before purchase and installation.