Well i went with the K@N, WOW the sound is differant. I think the performance is better as well, it really takes off when you step on it. Not sure how much the differance would make on a stock truck sense i already had Thorely long headers installed. Maybe a little backwards but at least its done now. Im glad i did it though, and everyone else on the forum is right, the mpgs dont go up very high cause the "heavy foot disease"