I've been told by others, (as well as dealers) that with todays engine's, a "break-in" period isn't necessary.
But I'm "old school" (a trait I got from my Dad), and for the first 500 mi., I'll be taking it easy. I'll avoid driving it at a sustained speed for the first 500 mi. as well. Then at 1000 mi., I'll be changing the oil.
Once I hit 1000 mi., it'll be time for some "stretching of the legs".