You can stop TEC from getting acces to any information.. they are not very good at getting it.

VAsari can see alll movements from your fleets..

Intel gathering is the Advent strenght: Advent see all culture in real-time so it can tell them where your CS and worlds are. Their culture influence vision works with with their superweapon, and one of their CS have a "farsight" ability that act as a instant scout on almost any world in the game. (sometimes i cant use it on some planets, but its uncommon, didnt notice a pattern yet)

Never saw a AI build a superweapon.

BTW, the TEC superweapon can, and will destroy your own planets if the shot was launched before you destryed/colonised the target. So in BIG maps.. letting it shoot at will be a bit of a nuisance. My friend had like 30 TEC SW going full at a central cluster (the map had 5 clusters, he controled 4 of them, only the central one was left and controled by the ennemy) so many shots were moving in it was just ridiculous, but it was so far away that shots took ages to reach their targets. So he would invade, colonise and all, then after a while realise that his colony vanished with his fleet intact above it.. then notice his own big bombs ram into his planet and blow it up.. again and again.