I switched over to Mobil One Tri-Synthetic a while ago. It seems to run a wee bit smoother with less vibration, but that could just be in my head.

It's good if you're in extreme driving conditions. It's really up to you, it costs a shitload of money ($5.85 a quart, 4.5 qrts. to fill my 6th gen. up).

Tests have proven no difference in wear between the two oils. It's your call.

I usually run Synthetic in the Winter and Summer and then regular OEM mineral based in the Spring and Fall. Winter and Summer are both extremes for temperatures.