Oh, and another point. If they have A.I.'s (which are presumably crazy-powerful, much like the rest of their culture), they should probably have computers.. which are likely extremely powerful, and if they can make star-sized vessels, they can make star-sized computers, theoretically. If they can make energy out of nothing, they can probably make a star sized or even greater mega-computer and upload their entire society's consciousness(es?) into the thing. Or multiple ones. Or one for each of their citizens. Hell, since they have unlimited vacuum energy, they can probably make a galaxy sized computer and calculate PI to the last digit.

I mean, once you get to a galaxy-sized culture that can screw around with multiple galaxies, nothing else matters.