I've been playing a huge galaxy game at tough difficulty with the Thalans lately and I find their power is absolutely mind-boggling if used intelligently. I started out by choosing abilities which nullified their population growth disadvantage, added to their economy, and industrialists government .. if I'm remembering correctly, +10 pop growth, +53 soc/mil, +10 econ, in total.
I did not, for a long time, have to at all build manufacturing matrixes, and when I did start, for the longest time I pretty much only used them, and the technology matrixes, on bonus squares. All worlds got star bases to begin with because there was nothing else to build and soon I was churning out small ships and constructors. With a lot of well placed markets/stock exchanges, and a trade for a +2 food farm, I had no problems. My empire only got better when I went evil and got the brain washing complex; the thalans can have sick, sick influence, even without concentrating on embassies.
Let me tell you that a manufacturing matrix on a +700 percent tile will either bankrupt you or be your capital ship-building planet forever. It's my personal opinion, after this game, which I'm just mopping up now, that the thalans are born and bred conquerors and that you will not need to build a lot of infrastructure to do so until your economy can handle it.