I've recently been trying to mod in my own civilization and a political party to go with it by means of the XML files, but have encountered quite a few problems.

The first thing I noticed was that negative bonuses don't seem to have any effect. At the start of the game, my civ had roughly -75% to military and social production (the general idea is that it's a race of happy-go-lucky, promiscuous people who're horrendously lazy) yet the homeworld could still construct buildings as quickly as any other race's. As the game progressed, I remained at the top of the industry graph even though I still had huge negative bonuses to production. The thing is, I'm sure I've seen someone from Stardock on these forums claim you can, in fact, use negative bonuses.

The next thing is the political party. Everything was going well until I tried to change my government to a Galactic Republic. Everybody refused to vote for my party, even though approval was around 90% and I was doing fairly well militarily, economically, and technologically. As bad as it was losing my party's 80% economic bonus and getting a -25% one in its place, I also discovered that attempting to switch back to an imperial government was impossible, not because no one would vote for me but because trying to get them to vote at all caused the game to crash. Losing control of the senate also should have meant that my party's -55% bonus to military and social production should've been lifted. However, there was no change in my industrial output, indicating the negative bonus hadn't been being applied.

Honestly, I'm not sure these issues are really bugs and not indications of my inability to mod the game properly. I read what I could about modding from the GalCiv Wiki, but still don't really know what I'm doing.

In case it matters, I'm running Dark Avatar with the latest version, 1.8f