Sacred Haven of Debauchery

Regarding this. There is a tactic involving early warfare, but it's rather specific, and I haven't personally tested it (I don't really like that kind of thing).

I once played through the game using that approach, but on a medium difficulty level. It resulted in a very fast playthrough, but it felt somewhat uninteresting and required a lot (and I mean a lot) of save-loading. And I don't think such a tactic is feasible with a large or medium-sized galaxy.