So I've been running Motorcraft Synthetic Blend 5W-20 in my Focus's for the past 10 years with no problems. The new ST takes 5W-30. Which is the same as my Mustang which I'm in the process of changing from Synthetic Blend to full Synthetic. My brother swears by Mobile1 Full Synthetic. But I don't exactly trust his opinions. I haven't had any issues with Motorcraft oil on my other vehicles and don't see a huge reason to change that. So I was wondering what everyone else was planning on running as far as brand goes and if they were going to run a Synth-Blend or a Full Synthetic.