Its the G85 package, it includes a Limited Slip Differential, or more specifically titled an automatic torque biasing dif. and Recaro seats. It'll help you a lot with traction and the seats will hold ya still in the twisties to keep ya from gettin fatigue from tryin to fight the g-forces tossin ya around inside the car. Each option by theirselves included in the package would cost (aftermarket)almost the amount of the package itself, and thats not includin labor if you have the LSD installed.