MMR13-1601

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

Additional Exhaust Clearance +15mmCreates additional space for larger-diameter aftermarket exhaust systems without reducing factory ground clearance.

Premium Construction Billet 6061-T6 AluminumPrecision CNC machined from aerospace-grade aluminum for exceptional strength, rigidity, and reduced weight.

Installation Direct Bolt-On FitmentUses the factory mounting points with no cutting, drilling, or permanent modifications required.

MMX Performance billet 6061-T6 aluminum underbody chassis brace installed on a BMW G82 M4, providing an additional 15mm of exhaust clearance while increasing chassis rigidity for improved performance and aftermarket exhaust compatibility.

Clearance Without Compromise

Engineered specifically for the BMW G8X M2, M3 and M4, the MMX Underbody Chassis Brace provides an additional 15mm of exhaust clearance while maintaining the vehicle's original ground clearance. Precision CNC machined from billet 6061-T6 aluminum, it delivers increased chassis rigidity and accommodates larger aftermarket exhaust systems without requiring permanent modifications.

MMX Performance BMW G8X M3 and M4 underbody chassis brace installed, showing the additional 15mm of exhaust clearance beneath the vehicle while maintaining factory ground clearance for improved aftermarket exhaust fitment.

15mm Additional Exhaust Clearance

Designed specifically to create extra space for larger-diameter aftermarket exhaust systems without reducing ground clearance.

Close-up of the MMX Performance BMW G8X M3 and M4 Underbody Chassis Brace on a white background, highlighting the precision CNC machining, billet 6061-T6 aluminum construction, and premium engineering details.

Billet 6061-T6 Construction

Precision CNC machined from aerospace-grade aluminum for exceptional strength, reduced weight, and a premium finish.

CNC machining process used in the development of MMX Performance products, showcasing UK design, engineering, and precision manufacturing standards

UK Designed & Engineered

Developed by the MMX engineering team in the United Kingdom, drawing on more than a decade of experience refining BMW performance products.

OEM Fitment

Installs using the factory mounting points with no cutting, drilling, or permanent modifications required.

Vehicle Applications

BMW M3 (G80 / G81)
BMW M4 (G82 / G83)

Clearance Without Compromise

15mm Additional Exhaust Clearance

Designed specifically to create extra space for larger-diameter aftermarket exhaust systems without reducing ground clearance.

Billet 6061-T6 Construction

Precision CNC machined from aerospace-grade aluminum for exceptional strength, reduced weight, and a premium finish.

UK Designed & Engineered

Developed by the MMX engineering team in the United Kingdom, drawing on more than a decade of experience refining BMW performance products.

OEM Fitment

Installs using the factory mounting points with no cutting, drilling, or permanent modifications required.

Vehicle Applications

BMW M3 (G80 / G81)
BMW M4 (G82 / G83)

Clearance Without Compromise

Precision Engineering From Every Angle

15mm Additional Exhaust Clearance

Billet 6061-T6 Construction

UK Designed & Engineered

OEM Fitment

Clearance Without Compromise

Precision Engineering From Every Angle

15mm Additional Exhaust Clearance

Billet 6061-T6 Construction

UK Designed & Engineered

OEM Fitment

MMX Performance BMW G8X M3 / M4 Underbody Chassis Brace

MMX Performance BMW F8X M2 / M3 / M4 Underbody Chassis Brace

MMX Performance BMW G87 M2 Underbody Chassis Brace