[GretchenGotGrowl]

There's some dyno numbers that show a slight gain in HP from running high-octane gas. Greater timing usually means more power. You don't need a tune in the V6 because it automatically adjusts timing based on the knock sensors.

All that said, the best way to find out for oneself is to run a couple of tanks of 91/93 octane and see if YOU feel a difference in power, smoothness, MPG.