This is a cheap and easy way to get the same or verrry close to the same performance as a CAI would give you... and it costs nothing!
DISCLAIMER: This is what I did on my vehicle and had great results with it. However, I am not liable if anything happens to your car because of this.
The airbox/intake modification:
You are almost definitely losing power with a cone filter, instead of the airbox in place, because of all the hot air that the cone filter is exposed to. Cone filters work on either a cold air intake or when being used with a heat shield. To further prove to you the power loss of a cone filter in place of an airbox, here is a dyno test from Techtonics Tuning of an open-element conical filter versus an airbox. There is quite a drastic loss in power with the conical filter. http://www.techtonicstuning.co...7.JPG
First, buy a high-flow drop-in air filter of your choice.
What I did, and what many others do, is modify the stock airbox. All you really need is a dremel, or maybe a utility knife, if that may work
Next, is cutting out part of the front/fender side of the airbox. I used a ruler and straight blade to slightly draw out where I wanted to cut exactly. I used many of the airbox’s lines to cut the cleanest looking cut. Some people swiss cheese the airbox, which in my opinion, is not the best method to go about this. You can just cut a whole clean piece out of the airbox. It will allow more air and look much more professional and clean. You honestly can't tell the airbox is modified if you do it in this manner.
Here are my pictures;