I've got a set of the Roush axle backs i'll be listing for sale as soon as i go snap the pics. Were on my neighbors 12 GT that had 3000 miles on it. They sound badass!
It has the Roush off road exhaust, Roush CAI, FRPP Rear LCA's and a Bama 93 tune. I can't hook with the stock tires so that will be next. Best so far is 13.6 @ 105.2. It's an awesome car.