https://www.helminc.com/helm/Result.asp?Style=helm&Mfg=FMC&Make=FRD&Model=MUST&Year=2024&Category=1&Keyword=&Module=&selected%5Fmedia=
(Don't buy the Mach-E one. They're grouped together under the site's search filter for Mustang.)
That S550 PP2 time was from a track battle with the SS 1LE where they put both cars on Cup 2 tires to equalize any OEM tire differences. Most of their laptimes are from cars running OEM tires or at least from non trackday tires. They had a note about the tire choice on their laptimes chart like...
Mine does the same at 90 and over. I have the same car as yours with performance package and magneride. No vibration in steering wheel or seat, so I don't think it's wheel balance or drivetrain.
The PDF and infotainment owner's manuals both have the wrong procedure for turning off the seatbelt reminder chime. That was copied from the S550 manual. The HTML online manual has the correct procedure...