on a n/a engine your engine sucks in air so if you make it breathe easier it will always help...what most people tend to generalize is the sound is louder and more aggressive and you think the car is that much faster when its is really not

the bigger the displacement the bigger the gains - but that is true with all mods...but honda engines do cram a lot of air through them in high rpms so you will get some added power but nothing significant