Republic at min.
We will need the technologies Warrior Code, Wheel, Iron Working and HBR long before republic finishes, even at max science speed. Right now we even have trouble with 1 Persian warrior, in 20 turns or so we can expect some immortals.
If we cannot trade for these techs with MIA, then we'll have to stop researching republic and switch to these techs. So republic at max could waste a lot of gold and will ot save that many turns anyway, with republic at min the investment is smaller.
The gold we save up could be used to upgrade warriors.
I guess it all ties in with the despotic GA scare. Personally, I don't mind to have a despotic GA. It's not great of course, but we cannot afford not to build our UU soon.