Subaru STi Pro-Level Axle/Hub kit is a complete rear system including both axles, hubs and ARP extended studs. The axles feature our our larger 36 spline, up from 32 spline found on the Level 5 axles, aerospace grade torsional axle bars, a billet ball & cage inner cv with our aerospace grade inner differential spline for the R180 differential, and a proprietary outer CV with a larger spline. The hubs are made to accomodate the larger spline and have both wheel bolt patterns for the 2004 (5x100) and 2005-2007 (5x114.3) applications are also machined to accept the factory ABS rings. Rated to 1200HP with a 1-year warranty.