what about this? or it's just bull?
"Do the Weapon*R Air Filters, filter dirt better than K&N / AEM / Injen Air Filters?
The Secret Weapon Air Filter is made of Polyeurethane Foam, which is rated at 300 Pores per square inch. Whereas the K&N / AEM / INJEN air filters are rated at 30-60 pores per square inch. This means that there is more dirt particles passing through the air filter to the engine when using their filters.
Why is the Secret Weapon Air Filter so much better?
The reason why the Secret Weapon Air Filter flows much better than any other filter on the market today is because of the specially designed Velocity Stack inside the air filter, it helps gather more air into the air filter and velocitize the air into the intake tube".
http://www.prostreetonline.com/x/weapon ... ntakes.asp