After being a life time Mobil 1 user I am switching my wifes truck over to AMSOIL Signature Series and EAO filter. 500 more miles she will have 12,500 miles on Mobil 1 Extended Performance 5w30 and filter, I am going to get a used oil analysis done and see how well that held up compared to the 10k run I did on regular Mobil 1...I will do a used oil analysis after 15k on the Amsoil and see how much longer it will last and go from there.