Lookin' under the hood of my girlfriend's sube I noticed that there were only two clamps at the top of the airbox and the rubber part of the air filter was visible at the bottom of said box. Not being a Subaru owner I can't say whether this is normal but I've never seen anything like this in any stock setup in any other car I've owned so I'm guessing someone broke off the bottom clamps somewhere along the way. Am I right?

There are plastic hinges at the bottom.

The box has to be rotated to about 90 deg to clear them to lift off.

 

O.

yep, very easy to miss getting the tabs in at the bottom.

 

probably been making a 'wooshing' or similar noise.