K&NCold Air Intake System: High-Flow Air Filter, Increase Performance & Acceleration: Compatible with 2000-2008 HONDA: S2000, 57-3514

First the good:The sound!! I never knew a 2.0 could sound so aggressive. Install this, and you'll find yourself grinning every time you open up the throttle. It's probably the most inexpensive satisfying mod you can do to your S2000. I didn't notice a huge increase in horsepower, but as you know being an S2K owner the car was designed so well from the factory that it's hard to get better performance out of additions like this. It did seem like the car climbed to VTEC faster than before though....it could just that it was more fun because of the sound it makes.Installation was fairly simple and straightforward. Some things to watch out for are the vacuum line check valve and solenoid. Just make sure you pay attention to how the plumbing for those work as you're taking the old tubes off.It leaves much more room in your engine compartment. Not that you can do much with the extra room, but the installation looks cleaner than the factory intake in my opinion.The bad:The parts seem hit or miss on quality. The plastic tube between the filter and the throttle body adapter especially. The filter itself and the metal filter housing (box) are very well constructed.It does make the car a little louder at idle - not that big of a deal though.Conclusion:The best bang for the buck you'll ever see out of a S2000 add on part. It's not going to give you incredible performance, but it does make the ride sound great. I would recommend K&N air filters over any other air filter on the market too. That's just my opinion, but I've been using them for over 10 years on numerous vehicles and have never had a problem.If you want to see if making this purchase is right for you, simply lift the latches and pull the cover off of your factory airbox. Close and latch the hood and drive around a little bit. The sound you get is close to what this system sounds like with a couple of exceptions. 1) the K&N intake sounds more throaty (not ricey). 2) you'll notice an annoying hiss with the factory cover off that you won't with this system installed.

Installed the unit 1 week after purchasing a 2004 S2000 which was stock. Needless to say, the S2000 now sounds as good as it like it looks. My neighbor noted that it sounds like it should. Installation took about 2 hours. Instructions could have been more detailed but were sufficient. Materials are basic, some of the connecting hoses are already planned for replacement with higher quality materials. The difference between stock and with this unit installed is evident when jumping on it, the engine now screams but doesn't sound like a weedeater on steroids. Definitely worth the purchase cost.

Installed on my AP2. I can’t believe KNN is charging $400 for this. Figured it’s a quality and well known brand. Boy was I wrong. Instruction blueprint lay out is decent. The instructions themselves are terrible and some of the instruction photos do not match the parts in the kit. Kit was missing 2 nuts and one screw and one of the nuts was an incorrect size, clearly not part of the kit. The tube itself seems cheap and not finished well. Purchased a $70 ebay kit for my Ap1 last year which is of much better quality. The sounds is good and the finished look is clean, but please do your research and buy something better people.

THE GOOD:I'll try to keep this succinct, As others have said, after installing this intake, I wondered to myself, Why the F didn't I do this years ago?The S2000, not exactly a quiet car in stock form is transformed into a goddamm screaming banshee demon! This is the way the S2000 should sound!I raced an Aston Martin DBS the other day, It was hard to tell which car was louder, though who was faster was a more easily answered question.Anyhow, to describe it best, I'd say the intake makes the S2000 sound like an ape getting F'd by a jackhammer, and makes VTEC downright brutal.THE BAD:As far as the quality of the components, they definitely were cheap as could be.The intake piping is made of plastic (which i guess may be better for not conducting heat than aluminum?) but feels cheap, and the inside isn't particularly smooth, which isn't exactly the most efficient way of piping air into the engine.The hardware, screws, bolts, and rubber couplings were very low grade, and didn't exactly come together like clockwork, thought there were no fitment issues.The filter was also small compared the the K&N direct drop in I had in the stock airbox.UPDATE: It's summer time here in Washington, DC and with temperatures upward of 100 degree's when I tell that b# please, the Intake is sucking in stupid hot air. It has bogged down performance, and made VTEC far less brutal. The other day when the weather mercifully relented, and it was only like 78, the power was back. However, in these brutal summer days, almost all of them in the 90's, the performance really is miserable.UPDATED: THE CONCLUSION:BUY IT NOW! Maybe, if you live somewhere where it is not brutally hot.