It reads like you are looking for something more tame than the abundance of aggressive diffusers on the market, yes?
The M8 has more of a Carbon Fiber exhaust surround, rather than something with additional extended slats with more angles, etc; it has subtle slats.
Something like the 3D Design upper part perhaps?
I currently have the Vorsteiner diffuser, but have been looking for something different. The 3D design unit caught my eyes, but with the additional part that connects to the bottom of the one above.