Reminds me a lot of the 350Z nismo rear. It completely changes the style of the Amuse rear. Really hard to imagine without seeing it mounted. Looks promising though!
Would it be feasible to design more of an undertray type diffuser? With the end of it matching the traditionally black piece under the rear fog light, but also continuing deeper into the car? A flat piece+fins
Kinda resembling this?
But ending at the exhaust tips and matching the face of the black part here
I feel like it that extends deep enough it could really help guide air out and avoid the gap in between the bumper and mufflers usually created by going with aftermarket exhaust.