Cusco LSD RS 1.5-Way Only Rear GDA/GGA WRX BR9 BM9

If you're looking to improve traction and handling on your GDA, GGA, WRX, BR9, or BM9, a limited slip differential (LSD) is a key upgrade. This Cusco RS 1.5-way rear differential is designed to put power down more effectively, especially when you're accelerating out of corners or dealing with slippery conditions. It helps prevent one wheel from spinning freely while the other sits idle, sending torque to both rear wheels for better grip.

The RS series from Cusco is known for its smooth engagement and predictable operation. This 1.5-way design means it locks up during both acceleration and deceleration, providing a stable feel during cornering. It uses a unique cam mechanism that allows for a more gradual lock-up on deceleration compared to a full 2-way differential, which can make it feel more manageable for daily driving while still offering significant performance benefits. The internal components are well-made to handle the stresses of spirited driving and track use. Installation involves replacing your factory open or limited-slip differential with this unit, which typically requires specialized tools and knowledge of drivetrain components.

When installing this differential, it's important to use the correct gear oil recommended by Cusco to ensure proper break-in and long-term performance. You'll also want to ensure your rear axle bearings and seals are in good condition, as this is a good time to address any related maintenance. This differential is a substantial upgrade for anyone serious about maximizing their vehicle's performance and handling capabilities.