BTKUSA F9X X3M/X4M Dual Diff Mount

FOR INTERNATIONAL ORDERS PLEASE EMAIL US BUILTTOKILL@YAHOO.COM OR DM US ON IG

ALL HARDWARE FOR ASSEMBLY INCLUDED 

 MADE IN SAN CLEMENTE, CA 🇺🇸

Currently have a large demand for this product we are working as fast as we can to fulfill everyone’s order. 

Wanted to clear up some pricing confusion on our diff mount recently👊

Originally, all diff braces (G8X w/ Bushing, G2X, & F9X) had a retail price of $599.99. For the F9X launch, we offered the first 10 units at $450 and the next 10 at $549.99 as an early supporter discount before returning to retail pricing.

After reviewing everything internally #1 we realize this has caused some confusion and #2 we’ve decided to lower pricing across the board to $559.99 due to increased material volume and improved manufacturing efficiency from the recent support. 

All customers who paid the original $599.99 pricing for the F9X brace have already been refunded the difference. We appreciate everyone’s support and apologize for any confusion.

The BuiltToKillUSA F9X X3M/X4M Differential Mount is designed to eliminate one of the biggest weak points in the drivetrain by adding additional support and reducing excessive differential movement under hard acceleration, launches, and aggressive driving.

The factory setup allows the differential to twist and shift under load, which can lead to drivetrain slop, inconsistent power delivery, and added stress on the factory mounting points. Our upgraded mount helps stabilize the differential by distributing load more evenly and limiting unwanted movement without introducing the harshness of a fully solid setup.

Built using high-quality materials and engineered specifically for the F97 X3M and F98 X4M chassis, this mount improves drivetrain response, traction consistency, and overall stability while helping reduce stress on the factory diff bolt and mounting system — a known issue on high-power BMW platforms.

Every component of the BuiltToKillUSA Differential Mount is proudly sourced and manufactured 100% in the USA. From machining to hardware and finishing, every part of this product is built domestically to ensure the highest level of quality, consistency, and durability.

One of the main things we had in mind when designing the mount was NVH. This is why we designed it to utilize a small 80A polyurethane bushing to help spread load more evenly. Across all our diff mounts we have had 0 NVH complaints so far. 

Features:

• Designed specifically for F97 X3M & F98 X4M
• 100% USA sourced and manufactured components
• Reduces differential movement under load
• Helps reduce stress on the factory differential bolt
• Improves throttle response and drivetrain stability
• Better traction consistency during launches and shifting
• Performance-focused bushing design without the excessive NVH unlike the leading solid mounted competitors
• CNC machined and built for long-term durability
• Direct-fit installation
• 80A POLY BUSHING DESIGN 

Whether your X3M/X4M is stock power or a fully built high-horsepower setup, the BuiltToKillUSA Differential Mount is designed to provide the support and confidence the factory system lacks.

PROFESSIONAL INSTALLATION IS RECOMMENDED AS A RIVET TOOL IS REQUIRED. VERY INEXPENSIVE TOOL THAT CAN BE PURCHASED ON AMAZON OR MOST HARDWARE STORES IF DOING A DIY INSTALL

ALL COMPONENTS FROM THE BUSHING, BOLTS, TO THE FULL BILLET ASSEMBLY ARE PROUDLY MADE IN THE USA.