Air filter Testing
 

http://www.nicoclub.com/archives/kn-vs-oem-filter.html

Very interesting testing and results. I do not agree with the author's opinions but believe the test results are accurate, informative and useful. IMO the bottom line is that the best filtering air filters will be among the most restrictive and "high-flow" filters all sacrifice filtration for reduced restriction and increased airflow. Something to consider.