[No Boost]

365 bhp/343 tq is more than sufficient for this car regardless of the designated engine code. To most buyers, the new M2's power will be defined as having 45 more hp than the old one. That's a bump that can be achieved by a downpipe or stage 1 type tune, so a minimal increase.

The S55 is very tunable and I see that as the only benefit over the N55 which is just as durable in stock form as the "proper" M engine. Furthermore, no matter how much the engineers tweak it, the aural pleasure just won't match the N55/exhaust combo.