i had a K&N drop in panel filter in my 2012 GT,6MT for around 4k miles.I read a post where SVT did a dyno test that showed it actually lost 4-5 hp on the 5.0.I took it out a couple weeks ago and the car feels more responsive,a little more peppy and i,m now getting almost 2mpg local driving better gas mileage.Ford got it right with the stock intake on the 2011 and up Mustang.The K&N is only good if you never want to buy another filter,it does nothing as far as performance on our cars.l