And 'stealth'!
Make it so only scouts can detect it.
While on that... everyone can 'see' mines. But they need a scout to "see" them. Why not make enemy mines completely unseen? I mean, if I KNOW I'm walking into a mine field, I'm going to bring mine detectors to kill them. If I don't KNOW, then I have to dedicate a chunk of my forces to mine detection out of pure paranoia.
Do that with the espionage ship, too.
