It's not heavy infantry, that's why it's not balanced. If all heavy infs would have that damage and pilas it would be great, but khuzait infantry costs 130g and it's far better than all other 160g melee infantry, that's why it's unbalanced.
Khuzait inf should be somewhere between peasants and heavy, it should be fast enough, should have decent armour, maybe some throwings (not pilas) and it definitely shouldn't have a weapon that deals twice as much damage as second best in the game
Or just make it 160g