I'm sure it was the V8 version just without the supercharger. A guy who lives two houses down from me has one. A friend of mine in the ol' MR2 club said they raced at the track since they're buddies and he ran a 13.5X to the Roush's 14.3X and that's with an exhaust and Trickflows. A normal Mustang GT will run mid- to high 14s. With exhaust and headers they can get into the high 13s but the Roush has so much extra weight they're usually in the low 14s, as this guy's was.