Good day, i found a seller for Trellith Structural Energizers who hs not completed +12 research, can he still upgrade +12's or do you need the research? if you do need the research, is it possible to use the artifact(s) but not apply them, then when i take the planet the un-finished ability is there to use?

You cannot upgrade any buildings you do not have researched. If he does not have 12s researched, then he cannot use the artifact on them.

Too bad, thank you for the info!