A very small gain in efficiency, it changes the way the marker sounds, and that's about it. To be honest your money can be best spent elsewhere.
Exactly. I would say though that the L7 bolt with a stock board will significantly reduce the sound signature, which is already quite low with the stock bolt. But that's it.
I honestly put one in my SP-1 only because when I turned my SP-8 internals into EOS internals I could not use the L7 bolt with that set-up anymore, so I got a new bolt stop and put it in my SP-1 instead. It was either that or the L7 sitting in my spare parts bin.
But YES you do keep the "anti-chop tech". I can shoot the most brittle of tourney paints (like Draxxus Gold) at full-auto and get 0 chops or breaks. Quite an amazing feat for a gun with no eyes.