OK, assuming you have the same airbox as I do...
You need to remove the airbox from the car, as the plenum opens on the bottom. Don't bother disconnecting the battery.
Follow the arrows....
Step 1, Undo the accordion tube from the box, then open the PCM compartment by removing the top two screws. The lid will hinge forward on tabs at the front. Set it aside.
Step 2, remove the PCM. It will simply lift out, then set it aside. DO NOT REMOVE THE CABLES FROM THE PCM.
Next, unscrew the 2 screws the core support mount, and the bolt at the top right, insisde the PCM compartment. Lift out the box.
Step 3, undo the filter wing-bolts, and remove the cover, and the filter inside.
Step 4, flip the box over and undo the five bolts that hold it together(red arrows), then pull the box open from the green arrows. Make sure to open it from the filter side, as the other end has a foam ring that attaches to both halves. Also, the foam seal at the filter end is attached to the filter side of the two halves, make sure not to pull it off with the lower half.
Step 5, there will be two white plastic baffles inside, simply pull them out.
Step 6, reverse the disassembly process to put the box back together. Make sure that the strip of foam at the filter side of the bottom is properly in place.
Step 7, enjoy your new-found whine.