what Eklypse39 said was very true, most exhaust doesn't gain any HP, just the freaking wrongful advertising to making people buying it. I've tried many exhaust on my 99 accord 4 cyl, and most of them doesn't gain much, especially for hondas you needs as much gained in mid to high ends. Not just that, most exhuast has crazy loud tone to it, and i hated that. I've tried the Apex-i WS sport thats pretty good for the price and sounds like stock. But then, i got the mugen exhaust from the integra,,,holly molly, that exhaust is like the king of all, theres no other brand in the market can really compare to mugen. Especially the twin loop design,,,shit, not just it sounds like stock, you literally can feel it, also it looks HOT HOT HOT......