After reading a lot of the posts and the other postings, I think I will probably go with the Castrol. Now the question is 10W 30 Or 5W 30. They both call for 5W 30 in their manuals. I Don't get cold enough down here to worry about low temps. But I see where some of it shears down. And I do go 5,000 between changes. Does the 5W give that much more milage? Oh yes beings I am getting pretty old my wife told me I should slow down some. I guess it makes her nervous, as she is a little bit older than I am. But WOW, on the Town Car, I was getting 20 to 21 miles per gal, at 65 to 70 or so. Now at 55, I am getting 25 to 27 miles per. I guess there is something good about growing old. That will probably be easier on the oil also. But one of the reasons I go 5,000 miles per change is, except for the pickup, all my trips are at least 20 miles most more, and a lot of them 150 miles. No real short trips.