I looked for Mobil 1 15W-50 to put in my 304 but couldn't find it anywhere in Sydney. I even rang Mobil and they told me either that I wouldn't be able to buy it or that I would have to use 1L or 20L containers ??????? Anyway, I settled on Mobil 1 5W-50. It is available EVERYWHERE Now everyone says this will shear due to added VI improvers but this oil is A3 rated. Doesn't this indicate it will stay in grade a long time? I plan to change it at approx 7000 km. Thanks.