Edit: This thread started based on other dyno work I was doing at the time. Let me clarify the fact that this will not increase power if you have the OEM filter installed. You MUST have an aftermarket filter in order to see power gains! Also, if you have a closed-end filter then you need to do this for power gains as well!
A few people have asked for a quick how-to for this, so I'll try to post up something visual. I don't have my snorkel anymore to show you, but when you pull back the black plastic you will see the difference between my pics and stock.
First you must pull the four push-pins out of the plastic where it attaches to the radiator support (just forward of the two intake runners) Also, I would slide the hood release out of it's holder where it makes the 90° bend. This will help you pull back the shroud.
After you pull back the shroud, you will see the snorkel on your car that is not in this pic. There are two push-pins on the drivers side and another push-pin on the passenger side. They are a little difficult if it's just you, fyi.
After you remove the snorkel you will see the plastic piece that keeps air directed to the radiator from under the whiskers. I only cut my drivers side (evidenced by the fingers), though others have cut both sides and some have even cut the whole top section. The only way I know to remove this (so far) without cutting is to remove the entire bumper cover.
Hopefully this helps. I would've set my snorkel in to show, but it went the way of the circular file. This is a mod that would never need to be reversed because incoming water would have to travel vertically 1-2" to get in the plenum, and dealerships won't be popping the top cover to verify it is installed. At a minimum, the snorkel must be removed for the additional hp/tq of an aftermarket drop-in air filter.
Edit: All of these pics are with the front of the car on the bottom. Sorry, that's just how it came out.
Sent from my stupid phone.