Travis 1963: I am surprised that only one other person recommended the oil that I am using: Motorcraft 5W20 Full Synthetic (not the blend).
Granted, you will have to pay a few extra $$$ to buy from the dealer to get it. You said you manage your vehicles with overkill - Motorcraft Full Synthetic is the overkill part. My understanding is that it contains a much higher percentage of group III components than Motorcraft blend.
My car is giving up a few hundred HP to your Mustang. However, I have used a few other oils for comparison (Toyota 0W20 and Havoline 0W20), and there is very little to be gained elsewhere under hard usage, that I can see. No engine vices, usage or strange engine noises.
As an alternative, try the Kendall 5W20 Full Synthetic (if you don't like going to the dealer). My understanding is that it is related to Motorcraft, with the addition of titanium.
Someone else will provide the link for the F150 "hero" engine teardown using Motorcraft 5W20 blend. It will sell you.