Heres my two cents on filters and oil for what its worth. Ive used the Mobil 1 20-50 since I purchased it several years ago with a HD oil filter. The Mobil 1 is usually fairly priced and readily available at the local big box auto parts stores in my area. I never bought into the Amsoil thing. Ive always liked OEM filters, whether its Motorcraft for my GT500, or AC / DELCO for my Duramax. I never had a engine issue with OEM filters. Im not a big fan of the K&N air filters just due to the fact there oiled. I went to a dry filter from S&B and a dry Airaid filter for my Chevy and Mustang. I dont like the mess of oil residue in the airbox or maybe getting on the MAF. I was tempted to buy the SE dry filter since It seems the Amsoil filter is discontinued however, I havent done the research yet to see if the dry filter flows anyless then the K&N does. Currently, I still have the K&N in the bike that I bought a few years back when I went topless. Back then K&N was my only option.