Resurrecting this thread rather than hijacking another one - it seems that of M1 ESP 0w30 and ESP 5W30, the 0W30 is considered 'better'. Here's is one recent thread on the subject: Mobil 1 ESP 5w-30 or Mobil 1 ESP 0w-30 | 3.5 EcoBoost in the PCMO subforum.
I went with the 5W30 on my first...