Just two suggestions I thought of
sensors are underpowered. can there be stealth modules that as they get better u need better scanners to see them? stealth would be really cool, but would have to make it so cloaked shios cant attack the same turn they cloak or decloak.
so, stargates? from my understanding they do the same thing as engines, so as you get better engines you shoukd be able to build better stargates.they could be like terror stars where they require several modules and you would need one at both sides. basically a ship in the same sector as a stargate, if its on, could travel super fastly to another stargate. you would have to own or be allied to both stargates, then turn them on and link them.