Jack up the left side of the car and support with jack stands.

Remove the left side rear fender lining.

There are numerous press-in plastic retainers around the wheel well. Remove them, and remove the wheel liner.

Now, you'll have a clear view of the intake air filter box.

Start here if you skipped the wheel liner steps above.

You can actually do all of the work through the engine bay (and a little peeking in the side intake). I wouldn't recommend this method if you still have the stock air box snorkel in place. It obstructs the view in the side intake, which is useful to see the air box clips when you can't figure out what's happening by feel.

Loosen the 2 x 7mm hex band clamps at each end of the rubber intake tube.

Remove the intake tube. It's going to be tough to move as the tube is not all that pliable and pretty much stuck to the throttle body and intake box.

Carefully use a large flat head or prying tool to dislodge the intake tube and slip it of both ends.

The air box assembly itself should flex a little if you need to create room to remove the tube.

Disconnect the electrical connector on the air box flapper solenoid.

Disconnect the electrical connector on the MAF sensor

Unclip the 2 metal air box clips at the outer end of the air box. If you didn't remove the fender lining - this will require some creative arm positions.

This image shows the top one from the engine bay. The bottom one is exactly the same orientation, but on the bottom of the box.

Press/pull the outer edge of the clip in the direction of the throttle body.

Open the air box on the far end and slide it outward slightly to unlatch the rear half of the intake box from the slots on the front half (visible on the side closest to the throttle body).

Wiggle the box apart.

If you wish to clean the intake box or are not using the wheel liner method, I'd take the intake box out of the car completely. To do so you'll need to disconnect the 2 vacuum hoses shown below. One from the flapper solenoid and one from the intake manifold.

Remove the old air filter. Note that now would be a great time to clean the Mass Air Flow sensor too.

Unbox and inspect whichever air filter you chose. I'm re-installing a K&N after cleaning it using this cleaning guide. Place the filter in place up against the half of the air box that's left in the car.

Note that the air filter has one square corner - that goes on the outermost top corner.

Make sure the 2 metal clips are oriented so that they don't interfere with re-installing the air box.

They swing outward toward the side of the car to lock, so swing them in and keep them out of the way of the air box and filter.

Now for the annoying bit. The outermost side of the box is going to be a pain to align with those clips, and the inner most side of the box is a bit of a pain to engage the slots.

Patience will help you here. Line up the slots on the inner most side, and attempt to slide that side of the box in place first. If you're lucky all goes well and the intake box and air filter all kind of slip into place.

If your less lucky, all for corners seem to mysteriously fight you. At this point, peeking through the side grills may help you see what's going on with those outer clips - they are most likely your problem.

Once everything lines up right and the air filter slips in place - you'll be able to snap the 2 clips over the air box cover. Celebrate when this happens.

If you removed the intake tubing, re-install it along with the 2 vacuum hoses, and 2 electrical connectors for the flapper valve and MAF sensor.

Re-install the fender liner and wheel if you removed it.