I agree with this completely. There's just no reason to buy this car and then hold it back from its maximum performance by putting 87 octane gas in it.
I do think the manuals are a little confusing on this point. In the ones I have, in one place it does say that 87 octane is recommended. However, as you pointed out earlier in this thread in another place in the manual it does say that the maximum horsepower is achieved on 93 octane. The clear message for anyone that cares about their car is to run 93 octane in it, or 91 if that's the highest you can get. I suspect Ford may want the best of both worlds here, telling people who are concerned about the higher cost of premium gas that they can run it on regular, while in a more obscure way letting people know that they should really be running premium. They should just tell people that they need to run premium period, as an earlier poster said. For me, it's been so long since I've had a car that runs on regular I barely even notice that pump when I go to the gas station.