Well, what you are describing is straight piping. I would not suggest that. It would be very loud and you would probably have some droning. I would Add some small aggressive type muffler; a single to double chamber. The muffler will basically allow sound to bounce around in it. When sound frequencies reverse and go back at each other they cancel themselves and that reduces the hummmmmm or muffler sound drone to some extent.
On the Macan you have a turbo that downpipes to a cat. Since all work is after the cat no errors are generated. No smog issues etc.