The BuiltToKillUSA Differential Dual Mount is designed to reinforce one of the G-series platform’s known weak points. Designed specifically for the G-Series M240i, M340i, M440i, and A90/A91 Supra, this system improves drivetrain stability while maintaining daily driving comfort.

Unlike most dual diff mounts on the market, this system utilizes a bushing rather than a completely solid chassis mount. This design helps prevent excessive noise, vibration, and harshness (NVH), allowing you to gain the benefits of improved drivetrain control without sacrificing comfort.

The BUILTTOKILLUSA Dual Diff Mount keeps the differential stable under hard acceleration, aggressive launches, and spirited driving. This reduces flex and sharpens overall driveline response for a more connected driving experience.

Installation Overview

This system requires drilling a single mounting point into the subframe. To simplify installation, a properly sized drill bit is included with the kit. All supplied hardware is stainless steel for maximum durability and corrosion resistance.

Key Features

• Introduces an additional reinforced mounting point to better control differential movement under load
• Enhances traction, throttle response, and overall drivetrain stability
• Utilizes a threaded steel backing plate for a secure and reliable mounting solution
• No rivet nuts or compromise hardware used
• Complete hardware kit included
• Includes required drill bit for installation
• Installation requires drilling one precise hole in the subframe
• Straightforward bolt-on solution with no need to remove factory mounting components

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.
• Spreads torque load more evenly under hard acceleration, launches, and aggressive shifts.
• Especially important on higher-torque vehicles where the differential tends to rotate upward under load.

2. Reduced Differential Movement

• Less movement results in more consistent driveline geometry.
• Direct benefits include reduced wheel hop, more predictable traction, and less shock loading on axles and bushings.

3. Structural Rigidity

• Manufactured entirely from U.S.-made 6061 machined aluminum.

Why We Use a Bushing Instead of a Solid Mount

Most dual diff mounts on the market utilize a fully solid mounting system—but that isn’t always the best solution for a street-driven performance vehicle.

Our system uses a high-durometer 80A bushing to control differential movement without completely eliminating it. Under hard acceleration and clutch dumps, the bushing compresses slightly to absorb shock, then immediately stabilizes the drivetrain.

This helps reduce unwanted flex while preventing harsh load spikes from transferring directly into the subframe and mounting points.

Benefits of the BTKUSA Bushing Design

• More controlled power delivery
• Reduced drivetrain shock and stress
• Improved traction under load
• Significantly less NVH compared to solid mounts

A fully solid mount may eliminate all movement, but it also transfers every bit of force directly into the chassis. Our approach delivers near-solid performance while helping protect the car and keeping it comfortable for street use.

Shipping & Fulfillment

• Rvngraceworks handles all fulfillment for this product.
• Ships same day or early next business day depending on order time and availability.
• Tracking information will be provided once the order has been processed and shipped.
• Please contact us prior to ordering if you would like to confirm current availability or estimated lead times.

Installation

Professional installation is recommended to ensure proper alignment and secure mounting.