Then get a population pre-boost (obviously!) and other relevant bonuses (or detriments, if something goes wrong.)

(One possible bonus: Whereas it takes 5 days to develop infrastructure and increase production accordingly, the infrastructure would already be pre-built to a certain extent thus take less time to complete.)

To those of you who would cite the "Prime Directive" preventing us from making contact with pre-warp societies, as Captain Janeway said, "To hell with it!" Besides, that is a Human directive; I am Inergon.

to hell with the "Prime Directive"

Have you ever tried to reason with pre-warp societies? I mean, seriously, those guys are idiots. At best, they're mud-grubbing peasants who think you are gods but haven't the faintest idea how to hold a sonic screwdriver or torque-wrench. At worst, they're cave men, spending all their time playing click-based games and trading pictures of cats saying the most idiotic things. They'd probably drain your patience and research banks flat in no time. Better to start with an uncolonized world or just bomb the primitives out of existence.

Hi, TNM. We can have several options. You can CHOOSE to bomb them out. You can perhaps enslave them.

I would choose to civilize them into a higher level of society. Put them in schools and training centers; teach them the everyday living of ourselves. (Would you be happy to teach medieval citizens how to shower and brush teeth? I would, some would, some wouldn't.)

Or, you can sell them weapons. (I probably would on one planet; not on another.) If you want to see them fight with your weapons, imagine a battalion of the US Marines finding a time-portal and going through it to find the Crusades invading the Holy Land in the Medieval period. The Marines decide to give the Crusaders our modern weapons. What happens then?

umm, Harry Turtledove, "Guns of the South".

Wouldn't many of us like to sit back and watch this happen on our colonies?