Need to upgrade your rear-end, why not choose one of these Heavy-Duty lite-weight full spools. SCW full spools will not only save weight, but will enhance the performance of your car also. In addition to performing better, increasing the life of your rear end by reducing crown wheel deflection, also no broken pinion gears or slipping clutches to worry about.Will fit all standard Borgwarner diffs as listed below. Nissan Skyline R31 all years. And early model Borgwarners with after-market axles. The item "Full Spool Borgwarner 31 spline bw S1 SCW" is in sale since Tuesday, July 24, 2012. This item is in the category "Vehicle Parts & Accessories\Car & Truck Parts\Performance Parts\Other". The seller is "arrow89" and is located in Parramatta, NSW. This item can be shipped worldwide.