Premium fuel does NOT have any benefit unless your car has been tuned for it. The V6 has not been tuned for it. The I4 and V8s have been somewhat tuned for it as premium is recommended, but not required.
Here's a study AAA did on premium fuel when a manufacturer has recommended it, but not required it.
http://newsroom.aaa.com/wp-content/u...rt-FINAL-2.pdf