Let's be clear here about driving a 2015/2016 Technology Package equipped GT350 on the street versus a "Track Ready" car that was intended for the racetrack.Most tech/base 2016 owners haven't had any troubles. Persistent high RPMs push the temps, and unless you plan on going to jail, not happening on regular roads. (yes, I'm know there have been exceptions, but it's atypical)
Ford made it mandatory to have coolers installed not only on the transmission and differential but also on the engine for all of the 2017 GT350 cars based on numerous GT350 enthusiasts tracking their 2016 Technology Package cars on road courses with Limp Mode not normally coming into play during street driven conditions unless as you mentioned if you plan on going to jail.
Been around many 2015 and 2016 GT350 Tech Package car owners over the last 6+ years who do not track these cars and have yet to come across an enthusiast who has had their car go into "Limp Mode" on the street including myself who regularly shifts my Tech Pack car at over 7000 RPM and in the desert heat.