I think the better question is, "why do you think you need it?
This is a good question, hopefully not because you were at autozone and saw there little spin the wheel demo with the plastic gears, all it really does is make the oil THICKER, would make no difference than switching from 5w/30 to 10w/30 but also remember thicker oils rob performance.
a good quality oil and regular changes and checks is all you ever need.
Remember different additives can cause chemical reactions and might cause SLUDGE in your engine.