Originally Posted by kardboard
^^^ That's an N54 engine.
THIS is N55:
The new M3/M4 is definitely designed from the N55: See the similarities:
I suspect that the two turbochargers are differently sized. You'll have a smaller turbo for the low range providing meaty torque and then a bigger turbo kicks in to maintain airflow and torque for the high end of the RPM range. Also, chances are, this will be a direct injection, which means it won't rev as high as the outgoing V8 in the current M3.
However, if BMW nail their software correctly, the new M3 engine will absolutely destroy the V8 in every parameter.