Subaru WRX/STi Rear Differential Bushing Kit - Kartboy - Hard (02-07 WRX / 04-07 WRX STi). This Kartboy kit replaces the factory rear differential bushings with hard-durometer polyurethane pieces to reduce differential movement and provide a firmer rear mounting for more direct drivetrain feedback.

Built for enthusiasts who want crisper response from the rear end, this kit is a direct-fit replacement that preserves factory alignment and fitment. The harder polyurethane reduces deflection compared to OEM rubber, limiting differential rotation under load and helping maintain consistent power delivery during acceleration and cornering. The material resists oil and road contaminants better than rubber, improving long-term durability. The kit includes all required bushings and metal sleeves for the rear differential, and installation can be completed with common hand tools or professionally at our shops.

Features

• Hard-durometer polyurethane to reduce rear differential movement
• Direct-fit replacement for OEM rear differential bushings
• Includes bushings and metal sleeves required for installation
• Compatible with 2002–2007 Subaru WRX and 2004–2007 WRX STi

Whether prepping a street, track, or daily-driven car, this Kartboy rear differential bushing kit tightens rear-end response without major modifications. Call us directly with any questions at 512-982-9393 (TX) or 562-981-6800 (CA). We have two locations in Austin, Texas and the Los Angeles, California area where we offer installation and customization services. If you are thinking about purchasing multiple items, contact us for shipping discounts. We install on premises at both locations.

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