I just got back from Auto Zone and I found the German Castrol Syntec 0W30. Most of the time, you can only find the USA Castrol. Plus, they were having a great deal. Purchase 5 quarts and a K&N Filter for 27.99. And they were nice enough to let me substitute a Mobile1 Filter instead. You save $20.95 with this deal! I thought it was worth me sharing.
To read more about UOAs of the German Castrol, Amsoil, Mobile1 and more, you may be interested in this thread:
http://my350z.com/forum/engine-and-d...-and-info.html
With my new VQ35 engine, I am thinking about doing UOAs on most or all of my oil changes to find the best oil for my engine. This is the first time I've tried the German Castrol. I currently have Mobile1 5w30 Synthetic.