You're wasting your time if you don't plan on gears and a tune right off the bat. Sure woke up my wife's GTS! Her car also had a K&N drop in ... that seemed like a waste of time to me. I've haven't had her GTS on a dyno but the seat of pants gauge made me think that replacing the K&N with a CAI was worth the time and money. I would pay attention to what Z28th1s posts ... he had a damn fast naturally aspirated V6 that has humbled many, many people.
2011 Shelby Convertible w/SVT Performance & Electronics Packages
2011 Shelby GTS V6 Convertible, AT, CAI, Aluminum DS, 3.73, Tune