The stock airbox does not allow enough airflow to get into the intake system. Drilling a set of holes in the airbox housing will open it up and allow more air to breathe into the engine.
First step is to remove the airbox cover located on the right side of the engine compartment.
When you do this you'll see the air inlet to theengine. These are more expensive way to accomplish the increased airflow to the engine such as cone filters, but in this case this is an easy and inexpensive way to increase the airflow and save you money for other mods. Place the cover of the airbox on a good working surface . As you can see, the increased open area is dramatic compared to the stock cover. Reinstall the cover and your done.