can you say marketing? you could make the same power with a pushrod 360 with a few tweaks, if it was power they were after it could have been done alot cheaper.
I carefully considered all these points I have a 03 mustang 3.8 and run 5w30 penzoil If a problem arises I will Just Change the oil back to 5w 20 before taking it to the dealer. If a question arises just say you have been using the other stuff.