Cusco LSD RS1.5 Front GDB(C) GRB GVB STI Impreza

This is the Cusco RS1.5 front limited slip differential (LSD) specifically for the 2004-2007 Subaru Impreza WRX STI models (chassis codes GDB(C), GRB, GVB). If you're looking to significantly improve your STI's traction, especially during spirited driving or on track, a front LSD like this is a game-changer. It helps put power down more evenly to both front wheels, reducing wheelspin and improving corner exit speeds. This is a 1.5-way type, meaning it engages under acceleration and also provides some locking effect during deceleration, which helps stabilize the car when you lift off the throttle.

Cusco is well-known for its performance drivetrain components, and this RS1.5 differential is built to handle the demands of a performance Subaru. It's constructed with robust materials designed for durability and consistent performance. The 1.5-way mechanism is a popular choice for rally and track applications because it offers a good balance of traction enhancement and predictable handling characteristics. Installation involves removing the front differential from the transmission and replacing the stock open differential with this unit. It's a job that requires some mechanical expertise and specific tools, so it's often best handled by a shop experienced with performance Subaru work.

When installing a new differential, it's crucial to use the correct differential fluid recommended by Cusco to ensure proper break-in and long-term reliability. This differential is designed to work with the factory transmission and drivetrain components, but it's a significant upgrade that will change how your car feels and performs. If you're serious about maximizing your STI's performance potential, especially in corners and under hard acceleration, this Cusco front LSD is a solid choice.