Air Silencer.....

it's the "snorkle" tube connected to your airbox, goes in the fenderwelll. I removed mine when I installed my k&n just to get the airbox back in easier. doesn't do anything. might be able to hear it suck air a tiny bit more, but, if anything, you'll draw warmer air in. Not worth the 5 minutes unless you're already replacing the filter.
 
The screen is inside the MAF. The silencer sticks into the fenderwell from the air box. If you car still has warranty I'd be not so quick to take out the screen but the the silencer rip it out when stick in your K&N.
 
The "air silencer"/snorkle is the piece of rubber tubing that goes from the Air box (which surrounds the airfilter), through and into the fender wall.

If u open the hood, and remove the airbox housing the air filter, you will see a rubber tubing that goes into the fender wall. Removing it will net you some horsepower (supposedly). I removed mine on my 98GT, but have not yet done so on my 2002 GT.