question....
 

what exactly does an aftermarket muffler do for you...they say on the package that it adds a few hp...is this tru...and i dont see how it works...i see how a catback does cuz its a whole pipe that goes from teh engine rite...but a muffler jsu makes noise rite..cuz i was thinkin of gettin one...and aslo do knn air filters give power or jus sound like a muffler lemme kno i'm new to the performacne field..

just a muffler isnt goin to much of anything...a straight-thru might up the hp a tiny tiny bit but nothing noticable...so...just remove the muffler (I did that while I waited on a new cat when I was doing my exhaust and I already removed the muffler and decided to hell w/ it)

and yes the k&n filter is gonna give you some more power over stock style filters...not a lot...but some

a stock muffler is made for sound suppression, hence muffler. Aftermarket mufflers are not made for sound suppresion, but rather for a free flowing exhaust. A stock muffler misdirects the exhaust gases inside the chamber slowing it down and creates back pressure. This back pressure causes the motor to have to work a little harder to push the exhaust gases out due to the added back pressure. An aftermarket muffler will allow the gases to just flow right out, for sound suppression they generally use packed fiber glass to deaden the sound of the exhaust gases(glasspack). So overall yes just getting a new muffler will make a difference, but nothing to get excited about. A muffler does not make noise, it's the exhaust gases that do.

A k&n filter will hopefully flow better than your stock honda air filter. But for a little better performance buy a new intake system to remove your restrictive airbox. It's up to you what brand, they can be had for as cheap as $50 or all the way up to $400.