Sins of a Solar Empire, is a bit old now but there's this huge mod out which really adds quite a bit to the game and so far has worked a treat. Something worth taking a look at for sure:
Read up on it here:
http://www.moddb.com/mods/maelstrom
Enjoy
Read up on it here:
http://www.moddb.com/mods/maelstrom
Enjoy