Might be a noob question, but what does the bullitt or for that matter any new edge mustang have for a diff? Open or limited. And if limited, how sturdy is it. I wanna put some gears in the rear right away and wanna know if I should upgrade to a godd limited slip diff. The only ones that I have experience with is the Auburns on my old 5.0 and I liked it. Anyone have any feedback?