Factors we need to consider while choosing an Aftermarket air filter - OEM
filters (pleated paper element, Foam and other types) generally offer superior filtration with acceptable levels of air flow at normal operating conditions but may not support high air flow applications. OEMs filter elements have smaller effective pore size thus helping filter out larger size particles out of the intake system. Due to this OEM
filters are often restrictive when you need a high flow air intake setup.
Aftermarket filters are usually based on cotton gauze type or the foam type. They support much higher air flow but may not be able to match the OEM
filter for filtration. This is mainly because of the larger effective pore size of the filter element that allows larger particles to get through the system while maintaining higher air flow. eg- if you run your finger in the intake plumbing, you may find more dust/particles in a performance air filter setup as compared to the OEM
In many cases if not all, high flow performance air filters compromise filtration ability when compared to the OEM
air filter. Not that this will do immediate damage but may effect the engine longevity a bit. Sometimes its worth it if you are looking at every last ounce of power from you race machine.