I've seen CATERHAM state several times that syn 10W30 was an obsolete grade. With my last oil change I used the remainder of my Mobil 1 High Mileage 10W30 so tonight in Walmart I bought the Mobil 1 High Mileage 5W30. I must admit some congnitive dissonance buying the 5W30. Years ago I learned that you should buy the narrowest range suitable for your climate to minimize the VII. I realize that it probably doens't make much difference in NC. Nevertheless, it is yet another example of BITOG impacting oil habits.