The MMX Billet Subframe Insert Kit is a precision-engineered solution designed to improve handling and stability on F-Series BMWs (F2X & F3X). By filling the voids in the OEM rubber rear subframe mounts, these billet aluminium inserts limit unwanted movement, helping to maintain correct suspension geometry and deliver sharper, more predictable dynamics.
Under load, BMW’s stock rubber subframe mounts flex, making the rear feel loose and vague, especially during hard cornering, acceleration, or launches. The MMX inserts solve this issue by eliminating slop in the mounting points without compromising ride quality or adding unwanted NVH (noise, vibration, or harshness).
Crafted from CNC-machined 6061-T6 billet aluminium, these inserts are built to last and will not wear over time. Installation is straightforward, fully reversible, and can be completed in under an hour, making this one of the most effective and affordable upgrades available for your BMW.
Key Features
CNC-machined from high-strength 6061-T6 billet aluminium
Fills voids in OEM subframe rubber mounts for reduced movement
No increase in NVH — refinement remains intact
Helps maintain correct suspension geometry under load
Sharper, more stable handling and improved cornering response
Quick installation with subframe in-situ, fully reversible
