So the last few days I've been studying filters and oil. My buddy is a sales rep and he was explaining to me that the filters with a wafer spring in the top are junk. Upon the 1st cold start the wafer spring is bent and the filter is basically in bypass mode from the moment forward. He went to explain that Amsoil, Wix, Napa and Carquest filters have a coil spring in the top of them so they return to regular filtering after cold starts and don't remain in bypass mode. After looking at all the cut open filters he was right...not even Mobil1, K&N or Royal Purple filters have this...,...I was surprised.