Built to Kill

BMW M2 M3 M4 (G8X) S58 Differential Mount Upgrade

SKU:
$1,499.00 AUD

The BuiltToKillUSA Differential Dual Mount is designed to reinforce one of the G8X platform’s known weak points. By utilizing the unused factory secondary bushing location, it adds a second support to keep the differential stable under hard acceleration, aggressive launches, and spirited driving. This reduces flex and sharpens overall driveline response.

installation is super simple. No disassembly of oem components needed. Insert the bushing assemble the mount on diff and BOOM…Unparalleled driveline support 

WHAT IS A DUAL DIFF MOUNT AND HOW CAN IT BENEFIT MY BUILD?

1. Improved load distribution

  • The mount ties both sides of the differential into the subframe instead of relying on a single ear or bushing.
  • This spreads torque load more evenly under hard acceleration, launches, and aggressive shifts.
  • That’s especially important on higher-torque cars where the diff wants to rotate upward.

2. Reduced differential movement

  • The billet bridge + side arms strongly limit diff wind-up and rotation.
  • Less movement = more consistent driveline geometry.
  • This directly helps with:
    • Reduced wheel hop
    • More predictable traction
    • Less shock loading on axles and bushings

3.  Structural rigidity 

  • All US 6061 machined aluminum 
  • Weighs only 20 oz for whole assembly

Our Type III hard anodized, also called hard coat anodizing, is a surface treatment applied electrically that greatly enhances the aluminum’s properties. Key benefits include:

    •    Extreme hardness & wear resistance — significantly harder than typical anodizing and often compared to hardened steels in surface properties. 

    •    Thick protective oxide layer that resists scratching, abrasion and corrosion. 

    •    Better surface durability under stress — ideal for high-use parts. 

    •    Good chemical resistance and improved ability to retain lubricants. 

This coating is compliant with MIL-A-8625 Type III standards, which is considered a mil-spec (military grade) finish for aluminum parts that see heavy use.

FITS G80M3/G82/G83 M4/G87M2

Special Order Item

This product is imported from overseas specifically for your order.

The listed price includes shipping to Australia unless otherwise stated.

Please note: Import duties, GST, customs clearance fees and any other charges assessed upon arrival in Australia are not included and remain the responsibility of the purchaser.

Important Information:

This product is intended for performance use and should be installed by a qualified professional.

It is the customer’s responsibility to ensure compatibility with their specific vehicle prior to purchase. If you are unsure, please contact us before ordering.

Gridline Custom Motorsports is not responsible for issues arising from incorrect installation, misuse, or improper product selection.

Due to the nature of performance parts, some items may be special order and subject to supplier availability and lead times.