I bought an STP air filter for a 2008 Subaru Outback standard 2.5. After I got home I looked in the manual and it said to use a Subaru brand filter as any other might "negatively" affect the engine. The only difference is the Subaru filter has a thicker orange coating on the inner pleats closer to the engine. I did compare the Napa Gold to the STP and they look identical and both made in South Korea. Any Comments? Thanks.