Ok, I'll go out a limb and disagree here. No, the short tubes don't add peak hp. What they do, from all the articles I've read about them in S197s, is move the power curve into the lower rpm range. Basically you'll gain mid-range hp from shorties and top end hp from LTs on the S197. Which is why everyone says they're worthless, because you don't see a peak hp increase which is what everyone quotes from dyno sessions. (The cars tested already had a CAI and tune, as well as pulleys I believe, so not sure if yours is stock). I'll look at a set of these eventually because I want to increase actual performance on the street and am not worried about winning a numbers game on the dyno or getting the best peak hp for high rpm situations at the track.