MMX Performance Underbody Chassis Brace

The MMX Performance Underbody Chassis Brace is a precision-engineered replacement for the factory underbody brace found on the BMW G8X M3 and M4. Developed for vehicles running 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 street and track driving.

Unlike the factory stamped component, the billet aluminum construction delivers increased structural rigidity while creating additional clearance beneath the vehicle. This helps reduce the possibility of exhaust contact without compromising ride height or requiring permanent vehicle 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 G8X builds.

Designed and tested in the United Kingdom, the MMX Underbody Chassis Brace reflects the brand's commitment to precision manufacturing, functional engineering, and performance-driven product development.

Product Details

• Provides an additional 15mm of exhaust clearance over the factory brace
• Maintains factory ground clearance
• Increases chassis rigidity for improved vehicle dynamics
• Precision CNC machined from billet 6061-T6 aluminum
• Optimized lightweight design without sacrificing strength
• Ideal for vehicles equipped with larger aftermarket exhaust systems
• Direct replacement for the factory underbody brace
• Uses original factory mounting points
• No cutting, drilling, or permanent modifications required
• Fully reversible installation

Fitment (manufacturer): Fits 2021+ BMW G80 M3, G81 M3, G82 M4, G83 M4 with S58 engine (manufacturer: chassis G80, G81, G82 & G83; model year 2021+; engine S58)

Brand: MMX Performance   Part #: MMR13-1601

Emissions: no CARB EO number is listed for this part. Check your state's emissions laws before street use.