??What oil should I use??
Without a UOA, advice is meaningless. Like with base maps, every car will react differently, so you should invest in a UOA yourself to see how your car reacts to the oil you're using. Get a kit from Blackstone for your next change, and see what's going on with your current oil, then consider switching.
Personally, I just made the switch over to Rotella T6, and am waiting to do a UOA at this oil change (I wanted to wait until I went through two changes before shipping a sample out).