Get the GT 500 , the Ford Engineers I have as friends, along with a couple of Pro Drivers would attest to the crazy speed and lap times of the Supercharged beast. We had one at the Mustang Roundup 2019 and they ( Ford ) beat the car all day on the track and it never hiccuped. Hard to get and with the chip situation it is likely to be rarer than the GT 350.
Glad Canada opened up the border for US citizens again,
Not that money should be an issue if you are buying a GT500 for a track car .
But, consumable wise and broken parts the GT500 would be considerably more. Though if you could harness the power of the GT500 it would be hard to beat.