which intake and exhaust systems will provide the most horsepower?

As has been discussed elsewhere, the ones with superchargers or turbochargers to put more air and fuel in there. I've never seen a claim for more than about a 10 % increase in horsepower with different exhaust and intake systems that are "passive". And generally the trade-off is more noise on both ends, and often more peakiness - more horsepower at higher RPMS, less at lower ones, because the systems are tuned for specific RPMs. It is probably heretical of me to say so, but I don't really think they are worth it. Unless you just think they are cool because of looks and sound, and whatever. I suspect this will start a dialog. I just want to hear from anyone who even gets a faster quarter mile time with only headers, air cleaner, and exhaust system, without new smaller tires or nitro or anything else. And what is the difference in your times? And even a faster quarter mile does not correlate directly to street performance, because drag engines are good when they are peaky, where street performance and autocross performance tends to suffer from a peaky engine. Regards, Ian

I'd have to agree. I put an AEM cold air intake on my car, & it really changed the sound coming from the engine bay. It's definitely louder. I dont mind it. It's kinda cool. I did notice a slight pick-up in hp, too. Can't speak for the exhaust.

I have a 95 EX Coupe. When I found it, It came with a DC sports ceramic 4-2-1 header and stainless cat back exhaust. It also has a no-name chrome short ram(not cold air) intake with a K&N like cone filter. I believe it has been chipped as I can run it well into the red if I want and Vtec kicks in at 5000 rpm. It made 120fwhp hp on Alamo Autosports dyno which is up about 16hp from the stock EX's 104fwhp that I have seen published. I'm guessing the cost of those mods runs close to $1000.00 based on DC Sports pricing. The sound is completely different from stock, the intake makes a loud hissing noise at idle and is louder with the AC on, with the windows rolled up it's not very noticeable. Give it a little gas and the exhaust drownds out the intake. I love the sound of the exhaust, it can be quiet at idle and slightly above, but 5000rpm and more it really roars. I run stock tire sizes (185/60-14) on aftermarket rims and have run 10.5 sec down the 1/8th mile local strip on an old, very soft, clutch. With stickier tires and a better clutch I'm sure I would see a noticable improvement. As it is, it spins the tires in first and when grabbing second and slips the clutch a bit in third. This is with 130,000 mile on the stock clutch, so I am trying to baby it a bit until I can afford a replacement. I do enjoy the occasional stoplight to stoplight race, and not much but V8 pony cars and turbos are really faster. I have even given a civic hatch hybrid a good run 'cause he lit his tires up and couldn't catch me in the short run to the next stoplight. On the highway, I had a relatively new camaro with the V6 (200hp I think) try to out run me, and we were pretty evenly matched on top, but at 110mph I had an edge which seemed to suprise the hell out of him :o) he probably had an automatic. I have also seen 130+ mph and had to back off 'cause I was approaching traffic(approx because the stock speedo stops at 120 but keeps on climbing). I do have nuespeed springs and lower strut brace, but I do not have any sort of additional bodywork and the car was very stable, but a little harsh, at that speed. All in all if it didn't have the power mods, I would do them. It's just that much more fun to own. Doug

i use a short ram air intake, and for the exhause i bought a borla muffler and had an exhaust shop favricate the rest of the pipeing in 2.5" exhaust pipe, much cheaper than a whole exhaust system and much better, you should give it a shot