$595.00 USD
$595.00 USD
























The MMX Performance Underbody Chassis Brace is a precision-engineered replacement for the factory underbody brace found on the BMW F87 M2, F87 M2 Competition, F80 M3, and F82/F83 M4. Developed for vehicles equipped with larger-diameter aftermarket exhaust systems, the brace provides an additional 15mm of exhaust clearance while maintaining the vehicle's original ground clearance.
Precision CNC machined from billet 6061-T6 aluminum, the MMX brace combines exceptional strength with reduced weight. Its optimized profile removes unnecessary material while preserving the rigidity required to reinforce a key structural section of the chassis, improving overall stability and dynamic response during both spirited road driving and track use.
Unlike the factory stamped steel component, the billet aluminum construction delivers increased chassis rigidity while creating additional clearance beneath the vehicle. This reduces the likelihood of exhaust contact without compromising ride height or requiring permanent modifications.
Designed as a direct replacement, the MMX Underbody Chassis Brace installs using the original factory mounting points with no cutting, drilling, or fabrication required. The installation is fully reversible, making it an ideal upgrade for both modified and OEM-plus F8X builds.
Designed and tested in the United Kingdom, the MMX Underbody Chassis Brace reflects the brand's commitment to precision engineering, premium manufacturing, and performance-focused product development.
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$595.00 USD
$595.00 USD
This product can expose you to chemicals such as lead and lead compounds, which are known to the State of California to cause cancer or birth defects or other reproductive harm. For more information, visit www.P65Warnings.ca.gov.
For a complete list of chemicals known to cause harm, visit https://www.p65warnings.ca.gov/chemicals.
Under the federal Clean Air Act (42 U.S.C. §7522(a)(3)), it is illegal to manufacture, sell, install, or use any part that defeats or alters a motor vehicle’s emission control system for use on public roads. Unless a product has received an Executive Order (EO) from the California Air Resources Board (CARB), it is not legal for use or installation on any pollution-controlled vehicle driven on public highways.
Some states have CARB-equivalent or independent emissions laws. Customers are responsible for verifying local regulations before purchasing or installing emissions-related products.
All performance, racing, or competition parts sold by this company are intended solely for off-road, closed-course, or competition use on vehicles that are never registered or used on public highways.
Kies Motorsports, LLC sells and markets these products for lawful use only. We do not condone or authorize the use of emission-control defeat devices or any modification that violates the Clean Air Act or state regulations.