While this is one of the most inexpensive mods available, it does give your vehicle a little bit extra. It's not like having a supercharged engine, but it will make a pretty noticeable difference for only a few hundred bucks and an easy installation. When you get your car with a factory air intake system, it's like your car has a stuffy nose. You can still go out and do your errands with a stuffed up nose, but things could be better, right?
If you put a cold air intake in, you're freeing those sinuses right up and letting your car work at its full potential. These intake systems move the air filter out of the engine compartment, which allows for colder air to be brought into the engine for combustion. Since the colder air is much denser, it contains more oxygen than the air from a factory air intake system. This gives you more power from the combustion chamber.
Again, while this isn't the most expensive modification in the world, it will allow you to get a much larger kick. In addition to getting cooler air into the combustion chamber, it also increases airflow. Instead of being stuffed up with an average amount of hot air, your car can be filled with flowing cool air and you can get your foot in the door with modifications!