Pretty sure all the marketing material on Amsoil is about the signature series which is a great botique oil but I don't think there's much out there on XL and OE which seem to be meant to compete with the stuff you can get off the shelves at Walmart or even the Autoparts store for a good deal less money.why is amsoil being criticized and doubted about there wear,cleanes,noack and what not like no other company? noboby doubt m1 for there cleaning ability,nobody doubt redline for there film strengh whats the hard on on amsoil?