What does the owners manual say?
I've got the V-10 also, and as far as I know, it takes "regular", though I wonder if that <87 Octane is a bio-blend...in which case, I'd suggest avoiding it.
You'll save money at the pump, but not down the road. The more alcohol in the gas, the less mileage you'll get.
And on the older engines, they weren't designed for these blends, so who knows what will happen to them??
I'm guessing that you're probably talking about 3-5 cents per gallon, so only an extra couple of bucks.....splurge:)