The 900HP Level 5 kit for the 1992-2001 Impreza STi (GC8) and 2002-2007 Impreza WRX (GD) with STi R180 Rear Differential Conversion is a complete rear system. Included are both axles, hubs, and ARP M12x1.5 extended studs. The axles feature our aerospace grade torsional 32 spline axle bars, increased from the factory 29 spline bars, and a billet ball & cage inner cv. Equipped with our high-grade inner differential spline for the R180 differential, and a proprietary outer CV with a larger spline. The hubs are made to accommodate the larger spline and are also able to accept the factory ABS ring. Rated to 900HP.