I had a 7-year relationship with Amsoil oil and filters for my Ford Contour SVT, which is a high-output engine. I found the once-a-year oil change, when I used their filters, to be a money saver, and using the oil gave me a MPG increase of about 2 MPG. I read all the information on it I could find prior to making the decision to use it, and was very impressed with its statistics. Bobs-The-Oil-Guy website will tell you all you need to know about oil and filters, and which ones are worth the money and which ones to stay away from. For me, Amsoil is superior to all the others, including Mobil 1 Syn., now that Mobil 1 is more than $10/quart, with tax, in my area of the country. YMMV.