The Nissan (Dynomax) performance exhaust was the first accessory I had installed, it was on before I left the lot. Personally, I like it; especially on the Supercharged. You get the whine of the S/C up front, under the hood and the grumble of the exhaust in back. The combination of the two makes it pretty cool! Horsepower increase? Maybe, but I doubt it. Hope this helps.