Consider also the following:
Cost of an OEM Air Filter - P1,100.00 (this is casa price and my car is a Lynx 2.0 RS); it requires replacement every 5000km; and in my case, I'll need 3 replacement in one-year.
Cost of a KNN Filter - P3,500.00 - P4,000.00; good enough for the entire lifetime of the car, i.e., if we are to believe the manufacturer.
I may not get a significant increase in HP using a KNN filter but certainly I can save quite a sum as opposed to using the OEM air filter. After a little over a year bawi na initial cost of my KNN filter.
