Hi I am new here and I tried to search but didn't see anything about it. I have a place by me that does Amsoil xl-7500 oil changes for 39.95. (37.95 if you bring your own filter) So my question would be is the xl-7500 good oil? I know its prob. nothing like the signature series but would it be a better choice then say mobil 1 or the like? Thanks for the help!