http://www.infobarrel.com/How_to_Buy_the_Best_Air_Intake_System_for_your_Vehicle
published April 18, 2009
One of the easiest and cheapest ways to increase performance is by adding an air intake system to your car. Most people don't realize that the stock intake on most vehicles is made smaller and restrictive to reduce noise levels, replacing the stock system with a new air intake system will increase mileage and horsepower.
There are several very important features to look for in a new air intake system that can have a real effect on performance gains.
Well, that will depend on the quality and features. They also vary depending on the size of engine they are designed for. K&N air intake systems are known for their quality and performance gains. You will, of course, find many links on this page to help you find the best air intake system for your car too.