Sorry, it wasn't very polite to ask two time ^^ But any player who know this unbalance can win against better player without any difficulties...
Last time I checked, I saw that Vaygr Missiles can be built on the Shipyard too.
Hmm, if their build time is increased no one will use them, because it would freeze the construction queue. I think it would be better to keep the fast build time and to reduce armor significantly (and damages). It would make them easier to destroy and the 3 or 4 interceptor that IA build at the beginning of the game could destroy it. But if that is done (reduce health and damages), research should cost no more than 2000RU, it would be too expansive for the utility these missile has.
It could be great to make Researches Upgrades to these Missile too (on the both sides). It would force the player to waste time and RUs in researching for an optimal use, and they won't be spammed at the beginning of the game anymore.
I think these missiles must be used as a support on fleet offensive, by targeting production ship when all enemy ships are fighting against our squadrons. But as they are now, they are a way to prepare an attack by destroying key-ships of enemy fleet, and that's too powerful. Only a full-epgraded missile would be able to destroy Stations in one hit.