ok i have a 2009 with pony package, i am confused because everywhere i read it says that they dont come with the limited slip diff.... i have done a burnout and i left two tread marks on road?? mine came with a rear sway bar already installed, is it possible it has trac-lok as well? i only ask because i am ready to order the 3.73 gears and need to know if i need to buy the traclok as well.