The MAD F9x Catted Downpipes unlock the real performance of the F90 M5 and F9x M8, swapping the restrictive factory downpipes for a high-flow catted design — now backed by a no-CEL guarantee. Expect quicker spool, freer flow and a deeper, more aggressive note.

Performance

• 300-cell high-flow cats for the right balance of performance and street drivability.
• Improved exhaust flow, faster turbo response and sharper throttle.
• Up to 30 HP on stock turbos — more with upgraded turbos.
• Flex section for added durability.

Build & fit

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

No-CEL guarantee & warranty

• If a check engine light appears due to the catalytic converter, MAD replaces the downpipes free — 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

• 2018+ BMW F90 M5 (including Competition)
• 2018+ BMW F91 / F92 / F93 M8 (Coupe, Convertible, Gran Coupe)

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.