
Some small risk of compromising fitration with the K&N at the expense of minor gain in air flow. Long story short - not as much difference in filtration vs. You should first look at and his exhaustive comparison test on the different types of air filters ("Air Filtration Test" tab). Najibs wrote: ↑Opinions? Experiences? Let's hear it. If it just means I won't have to keep buying regular filters, then that's a non-issue. But, If I'm compromising the engine by letting more dirty air in, then it may not be worth it. So, my dilema is.should I replace the standard filter the car comes with for a K&N filter, or not? I'm not expecting a surge in power, but if it gives it an extra horse or two, that would be nice, as well as better fuel economy. In the long run supposedly it can hurt your engine. Some say it will improve fuel economy by restricting less air into the engine, while others say it's not worth it because you're letting more crap into the engine by filtering less and allowing more air in. Meanwhile, a mechanic told me that the reason people think this is true is because the K&N filter allowing mroe air in, is louder, therefore creating the illusion of having more power. I realize it's not a cold air intake that could all 10hp or so, but some are saying at lower RPM's the car seems more peppy, and at best it can add 1 or 2HP. Some people say it adds a bit of power, while others say it adds no power. I'm referring to the drop in air filter, not a cold air intake.

First off, it's for a 2.4L 158HP Toyota Matrix. I've heard mixed reviews about K&N air filters.
