the E30 vert in the first seconds isnt an M3, not so sure about the one @ 1:08 - 1:10 even though it has an M badge
.....but the one I let through @ 3:57 in this video is a real M3 convertible with a Nordschleife-Pro at the wheel.
you already can hear it rev behind me ~3:35
http://www.youtube.com/watch?v=9OoNQV5vMVM&feature=player_embedded