Deadshot pack

Shane: What the heck is a “Deadshot Pack?” I see them on the trade screen but can find no reference in the encyclopedia. Also, how does the “link” module work for the weapons (I traded for one). Does it kick in automatically? My “home” has been moved to the Santa Romira system (I love the way they take things for granted in this game — the freighters just showed up before I could say yeh or nay). Finally, are the REM fighters of any value. I was promised one after the “Momma Wolf” mission, but it was never received. I see there’s one for trade, however. Thanks (as usual).