Limited-Slip Differential

An open differential sends power to the wheel with the least traction — which is exactly the opposite of what you want when cornering hard or accelerating out of a turn. A limited-slip differential (Quaife, OS Giken, Wavetrac) distributes torque to both driven wheels, keeping the car planted and allowing you to get on the power earlier in a corner exit. On FWD cars, it eliminates torque steer. On RWD cars, it enables controlled, predictable slides. It's the mod that separates a car that understeers into guardrails from one that rotates on command.