You pussy footing around with all these little 4 bangers and you have a Mustang with an independent rear suspension already. Well, really, you have a Mark VIII without air ride and the weight. Which means find you a Mark VIII's 32v DOHC V8 (you know, the one with 290 hp?) and mate it with a Tremec T56, limited slip from the Mark, custom make the shaft, throw some Ford racing cams in it, and chip it and you'll destroy quite a few cars on top end. And you'll still pay the same insurance without the mustang premium.