Kartboy - WRX / STi Rear Diff/Carrier Wedgelock System

The Ultimate Rear Differential Lockdown
If you want to eliminate drivetrain "slop" once and for all, the Kartboy Rear Diff/Carrier Wedgelock System is the heavy-duty answer. While most kits on the market use polyurethane or elastomer inserts to fill factory bushing voids, Kartboy's Wedgelock system utilizes precision-machined aluminum inserts to create a solid mechanical lock. This ensures that every bit of torque is transferred directly to the ground, eliminating the "thud" and oscillation often felt during aggressive shifts and hard launches.

Stealth Performance & Bulletproof Build
Designed and manufactured right here in the USA, this kit is finished in a "Stealth Black" anodize. This not only provides maximum corrosion resistance but also keeps the upgrade discreet for those who prefer an OEM+ appearance. The kit includes the main differential bushing inserts and four carrier inserts, providing a complete solution for the rear subframe and differential interface.

• Zero-Deflection Design: Machined aluminum construction provides a more rigid connection than rubber or poly inserts.
• Faster Power Delivery: Minimizes differential rotation to provide instant throttle response.
• Stealth Black Finish: Anodized for durability and a low-profile, "sleeper" look.
• Easy Installation: Can be installed with basic hand tools in under an hour.
• Made in the USA: Built by Subaru enthusiasts, for Subaru enthusiasts.

Fitment Applications:

• Subaru WRX: 2015, 2016, 2017, 2018, 2019, 2020, 2021
• Subaru WRX STI: 2015, 2016, 2017, 2018, 2019, 2020, 2021

Technical Specifications:

• Part Number: KB-003-Wedge
• Material: 6061 Machined Aluminum
• Finish: Anodized Black
• Kit Contents: (2) Main Diff Inserts, (4) Carrier Inserts

Which one is right for you, Aluminum vs. Elastomer?
While Whiteline's elastomer inserts are great for a daily driver that wants to keep things quiet, the Kartboy Wedgelock is for the enthusiast who wants zero movement. Expect a slight increase in gear whine (NVH), but in exchange, you get a rear end that feels 100% connected to your right foot.