Only 2,500 "civilized" Benelli M4's will be sold. I've seen them in stores for the paltry sum of $1,500 and up.
You'e better off buying an M1 Super 90 Tactical for half that price.
What do you get for $1,500? A castrated, look alike toy. The stock isn't fully collapsible like the real thing. It only rotates around the axis. The mag tube is cut to a MAX capacity of 5 rounds and a metal extender is attached to give it the profile of a full length magazine.
The cool features that actually function are the optics rail and the round charging handle. These have similar aftermarket counterparts, but I'm hoping that they'll be available through Benelli parts dealers.
That said. The M4 appears to be built on an M1 receiver. In addition to the rail and charginf handle, the barrel, stock and mag tube are different. The bolt and sights appear the same. Perhaps it's only a matter of time before spare M4 shotgun parts migrate from the official supply chain and onto the civilian market.