Terror Stars are fluff. I only used them in one game. They are completely useless the way they are at the moment. I had one dissapear but it was still there. I just happened to click on what I thought was empty space and I accidently found my terror star, the galactic teddy bear. All graphics for it were gone and it had moved away from the star it blew away. But before I could get my fleet to defend, again, my new found "superweapon???", it got blown away.
They are useless. No movement. No defensive weaponry. (Perhaps it could be changed so it can only fire at ships when attacked, *hint to devs*, not when it moves to attack ships.) If you have the time and resources to build and maintain a terror star then you don't need to. The game can be won much quicker without them. All they are is a note to the AI that the human player is an idiot because the human player has just built a big, fat, slow, expensive target with a sign on it that reads: "I'm an unitelligent user and I want to attempt to lose a game I was winning against the AI's. Please come and kick my butt."
(I didn't lose that game by the way. Probably because I didn't build any more.)
Basically after a terorr star is built you have to protect the thing from a transport that has weapons. And while your garding this "awsome powerful" cuddly weapon the AI, if its smart, attacks your empire that is the farthest away from your teddy bear and your left with a big fleet moving 1 parsec a turn because of the ball chaining them.
I've yet to see any AI on any setting build one, even my friends who play it never ever see any AI build one, we do not play on the lower levels. Although we haven't conqured "suicidal" yet. And yes many of you are much better at GalCiv2 then my firends and me, I'm not attempting to boast here just making a point that the AI doesn't touch these things, from what I've seen.
Basically it you can build a terror star then don't, you will win much faster if you don't. I'm starting to think Stardock has a different sense of humor than normal peiople. They're probably laughing there bodies into shape thinking about how stupid everyone is for building terror stars just to see the graphical affects of a solar system we can't use get blown away. At this point that's all they are good for.
C'mon devs, at least make terror stars modable. If I understand correctly then they have been hard coded?