[Suicide Junkie]

Adding the tech area would be easy.
Adding facilities that give you those abilities requires hardcode changes.

Note that you would not be able to cloak your transmissions once you have ever sent any.
The first transmissions would take years to arrive at the next star systems... you would be left with a shell of radio noise expanding away from your planet.

Another thing about pure radio detection. If it takes 4 years for transmissions to get to the nearest star, by that point, most empires will be spanning a large lumber of systems and have made contact with races much farther than one system away.
The SETI stuff would have to be based on FTL communications in order to be worthwhile.

An FTL comm scanner would get you a very similar effect to the Ancient Race trait. You can see planets around other stars in realtime, and detect the signs of civilization.
(Hint: Medium sized planets that have equal value across the three resources, and are close to either 80%, 100%, or 125% depending on the game settings)

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I like the idea for having different actions available depending on how far apart your civilizations are.

Note: everything below would require hardcode changes, and may only appear in SE5.

Something like multiplying the cost of an intel project by one plus the number of systems between you and your target.
Intel ops against core worlds and ships would be much harder than ops against ships and planets in your own systems.
Trade could work the same sort of way. Research alliances might not be affected, since you could transmit the data.