I agree, return it. Why not stick to your OEM box? If you are looking for noise...you can do the intake silencer removal. If you are looking for power, you will need to look someplace else. These engines are picky with what intakes you use. As it's been proven over and over, that the OEM intake is good up until our tuner tells you otherwise.
Please read the following from
2point5RS_Dan about intake and filters;
Filters and intakes come up and I haven't written a big ol' condescending effortpost in a while so buckle in and lets take a look at some real info and not just some second hand ricer bullshit which we would normally see, aka 15 posts of MY KN IS AWESOME GET ONE blah blah blah shut up.
So the first thing I go to is miata guys. They're usually engineers who go to the deepest details. Two seconds of googling dumps this thread:
http://forum.miata.net/vb/showthread.php?t=420216
Not a lot of concrete evidence or links like I'd expect, so I dropped miata from my search string.
Ah bob is the oil guy
http://www.bobistheoilguy.com/airfilter/airtest1.htm
Some interesting stuff, but subaru owners are stupid, poor, and have the attention span of goldfish, I doubt any of them got through the first paragraph.
On to the next one:
http://www.nicoclub.com/archives/kn-vs-oem-filter.html
This one has graphs breaking up the words, so I think some people might be able to stomach this one. Basically KN lets a lot of flow through, but more dirt.
For all the stupid ADD people, just watch this and realize LOVING with your intake is dumb: