"Onagers vs Kungas" Topic

Many ancient rules note onagers as the beast pulling the Sumerian chariots, with penalties to reflect the onager's pleasant disposition. Yet the little i've read seems to indicate that for onagers read kungas, which are a donkey/onager hybrid. Since the kungas were easier to tame would the onager penalties still apply?

I think a bigger handicap for Sumerian Battlewagons is the mono-directional wheels and the simple weight of them, so I wouldn't fret the point about bitey equids too much!