What are your favorite non - OEM air filters to use ? After my Hyundai OEM air filter became dirty after 15,000 miles I tried a STP air filter (bought what Auto Zone had in stock) but found it to be too loose a fit and resulted in a UOA with increased silicone noted . I went back to Hyundai OEM air filters which have a tighter fit / seal but of course at 3X the price of the STP air filter . *I read that Wix and Purolator air filters get good scores in the criteria air filters are measured against one another - I would want to check for a snug fit to be sure it doesn't wiggle loosely once inserted .