The stock differential assembly is a torque sensing unit. Although Toyota built a great differential, TRD has designed a better one. The TRD differential is a true limited slip with clutch packs and will work better in a drag racing, road racing or just plain street enviroment. TRD didn't stop there when they made this unit, they built it with much beefier spider gears inside to wistand the added abuse of high HP Supras. This is the perfect unit for high HP Street Supras.