Driveshaft Shop X4 800HP Rear Axle - Subaru WRX STI (GD) 2004-2007

Driveshaft Shop developed the X4 line for fast street cars that still get tracked, and on the GD chassis STI the rear axle is rated to 800 HP. The shaft runs a 300M axle bar and a 300M splined stub inside a chromoly CV housing, a material specification chosen for torsional strength and fatigue life the factory Subaru rear axle cannot match. It is a direct bolt-in that uses the stock rear differential and hub, so nothing on the car has to be cut or machined. The axle is sold individually, so two are needed to replace both sides, and Driveshaft Shop backs it with a one year warranty.

Specifications

This part fits:

Shipping

• In-stock orders placed before 3 PM EST ship the same day — everything else ships within 24 hours.
• Standard, expedited, and overnight options at checkout.
• Oversized items ship by freight and take longer.
• Backordered items ship as soon as stock lands — contact us for lead times.
• International orders: prices do not include VAT, duties, or import fees. Your country charges these at import and they are the buyer’s responsibility.

Returns

• 30-day returns on new, uninstalled items in original packaging with all hardware.
• Standard returns: 8% restocking fee, buyer pays return shipping. Both waived if the item is defective or we made the error.
• Installed or used parts can’t be returned — confirm fitment before you install.
• Special orders and custom items are final sale.
• Email us for return authorization before shipping anything back.

Full details: Shipping Policy · Refund Policy