Another great shop for diff install is Unitrax in Anaheim (
Unitrax • Differential and driveline parts and service. Ratio Changes & Overdrives. Axle Shafts. Using parts from the most reliable companies in the drivetrain industry: Dana Spicer, American Axle, US Gear, Timken, Gear Vendors, OS Giken, Autotech, F)
They work on a huge assortment of cars, from street to full blown race teams. They even apply a ID number plaque to the differential casing so that they can track the date of install, who the installer was, and any other special notes.