in short . Capability to immediately respond to variable road conditions . it not only provides better traction, it also enhances the general performance of a vehicle. There is a marked improvement in total tractive effort as compared to open or conventional limited-slip differential equipped vehicles. In addition, it also allows the engine's torque output to be used more effectively, delivering more horsepower to the road.
If your going to be serious about road racing it's a must. I was shocked in the difference from when I switched .