Savage would last perhaps a few minutes against a toying Kun but all-out Kun destroys him before he has an effect on this bout.
Greater speed? check.
Greater strength via rage? check.
Greater TK? check.
Greater Force defense? check.
Greater FL? Savage nor Maul for that matter even wield it.
Greater Force Augmentation? by tiers.
Greater Sorcery? neither of his opponents wield it.
Greater Saber ability? Maul is of the same tier, Savage isn't close.
Greater Force Power? by so much it's a joke.
Kun is the most powerful in the Force here by a decent amount and has tiers more knowledge of the Force, Maul is the only one that can actually duel him here.
Let me check through my copy of TOTJ and get back at you:
Its unclear whether or not he was amped by Nadd at this point the quote says:
"Standing on the threshold of the future, Exar Kun senses a power moving around him..a power that wants to help him-Tales of the Jedi
Granted, Kun wasn't a fully-devoted darksider and was in conflict between Nadd and his (then) Jedi self, and its unclear as to whether dark rage was the source of his power. But Nadd could've helped him at that point, I'm not sure.