All I can say about additives is if you feel like you need to put something in to help your oil out, the oil your using isnt good enough! Think about it like this, if your using lucas, all its doing is increasing oil viscoscity, why not just upgrade your oil in the first place? And while im blabbering on, everyone please use either motorcraft filters or aimsoil filters if your going with an extended drain interval, as the OE filters are built for the pressures and filtering capabilities of our engines.