The MAD S58 Catted Downpipes are the upgrade for G8x owners who want real power and a deeper tone without inviting a check engine light. Running 300-cell high-flow catalytic converters, they free up the restrictive factory downpipes while keeping the car streetable and clean.

Performance

• 300-cell high-flow cats that sharpen sound and drivability while staying CEL-free.
• Up to 30 HP on stock turbos — more with an upgraded setup.
• Smooth, flowing bends for maximum airflow with no added drone.
• Flex section built in for long-term durability.

Build & fit

• Premium 304 stainless steel, engineered to handle extreme heat.
• Direct bolt-on with spot-on fitment — no cutting or welding.
• Compatible with both the factory exhaust and most aftermarket systems, and with right- and left-hand-drive cars.

No-CEL guarantee & warranty

• If you get a check engine light related to the catalytic converter, MAD replaces the downpipe free — guarantee valid for 2 years from purchase.
• Lifetime warranty still applies to manufacturer defects such as cracks in the pipe or welds.
• 90-day return window; ships in 1–2 business days.

Fitment

• 2021+ BMW M3 (G80)
• 2021+ BMW M4 (G82 & G83)
• 2023+ BMW M2 (G87)

Emissions disclaimer: This product is not legal for sale or use on pollution-controlled vehicles operated on public roads and is intended for off-road, race, or closed-course competition use only. You are responsible for compliance with all applicable emissions laws; use on public roads may violate the Federal Clean Air Act (42 U.S.C. § 7522) and similar state laws. Please check your local regulations before purchase and installation.

Sourced by KORE SPEED — Canadian-owned. Fitment questions? support@korespeed.com.