So, this image is circulating the web, is it really that big of a deal? People seem to be equating a quad exhaust with an M car. M cars have not always had quad exhausts, E36 anyone? E34? E30? E28? Frankly, for an N55 I6 a large piped single would be preferred and more efficient. If this is a true dual exhaust based on a split manifold, it would mean the car is running an N54 and two turbos. Otherwise, the exhaust is just for looks.
Here is the N54 twin turbo manifold to get an idea:
If it is an N55 a dual exhaust would not make any sense for performance. Clearly, a hopped up 1 series is coming, with either of these motors. Just tell what it is called already, and let's get on with our lives.