It's early doable, as believe it or not the 2.0 exhaust actually exits the box as twin pipes before its joined into a single one! And the same at the rear, the single pipe from the engine splits into two as it enters the box, couldn't believe it when I saw it. I presume is bmw's way of making the 2.0 appear lesser than the sixes, but it obviously needs the twin in and out pipes for flow otherwise they wouldn't have gone to the expense.
Mike