904 kickdown Q

The stock VB, with a wired-back throttle valve, will downshift according to command of the governor. On the street this is gonna have the potential to spin the car out, when it unexpectedly downshifts on closed throttle deceleration.
I imagine it wouldn't be much different on a track.
To prevent that, you would have to reprogram or eliminate the governor, or modify the VB. Or, just install a manual-shift VB.