My 2015 Mustang Owner"s is telling me I should use 87 Oct Fuel but Ford's web site for a 5.0L engine to use 93 Oct. I'm confused. In the manual they show a 5.0L with a cross brace above the motor my motor has no cross brace what's up with that? The manual also is telling me my top speed is factory set at 80 miles per hour is this correct? Maybe I am not understanding the Manual.