well, the amsoil is designed to go longer between changes. so while you'll go to wallyworld for cheaper oil, you'll make more oil changes than me and it'll cost u the same or more. the amsoil series 2k is like 7/quart. i do one oil/filter change a year and a filter change/oil top off at the 6 month mark. the average oil change ends up being around 10-14k miles. i've labtested the 14k oil and it was still good enough to continue using
