It's at least the most compelling argument I can find and it lines up with some of the cylinder scoring found in some cases. I doubt Ford will ever release a definite reason for it, though they must know what it is by now since they literally have multiple testing facilities to figure that kind...
I have a 21 mustang GT manual base with about 1200 miles on the clock. When driving there seems to be a somewhat quiet tick heard from the front end. It seems to be RPM dependant, not speed dependant. Happens even when warmed up and you can hear it inside the car with the windows up. Doesn't...