I've read various articles about the viscous typed center differential on normal 2.5RS and WRX (not sti)will lock-up whenever the speed difference is too big. So once you applied handbrake, the center diff will also tend to slow down your front wheels too since it's auto locked-up, thus applying throttle after pulling handbrake won't get you out of corner faster, but rather.. damage you car.
Anyone has tried so?
the only disengaging center diff will be on STI for which upon handbrake it will immediately free the center lock, thus, you are actually driving a FWD at that moment to allow you cut hairpin corner easier.