The thing with any F10 the sensation of speed is deceptive in this car because of all the sound isolation and the rock solid chassis. I always find my self way above the speed limit and not realize it until i look down at the tach.
I would imagine the acceleration between the 550 and M3 to be very similar even though they don't feel like it.
Here's a video i found of a M3 vert against a 550. Both stock. The M3 coupe would probably be pretty even or only barely edging out the 550. A simple tune for the 550 will be game over for the M3.
(start watching at the 30sec mark)