It is not "straight" plug and play, but pretty darn close. You need a later model screen, but since you already have the sony unit with the big screen, you don't need to source the mounts, faceplate, etc.I have a pre facelift focus which came with the Sony head unit with sync 1 I believe, is the sync 3 unit straight plug and play or is it a bit more complicated?
The biggest thing is the harness, I got mine (and most of my other parts) from this guy
I've been VERY happy with it so far. The android auto works great, the camera interface also works great (I had to add a camera to mine as it's an SE that didn't come with one). You'll need ForScan, the updates to the latest build of Sync 3, and a OBDII dongle (I ordered the one from Forscan) to interface with your laptop.
I'm very happy with mine.