I had a full Remus on my F90 M5, a fraction of Akra and arguably just as good sounding although Im biased.
The quality of the metal and welds are excellent and the sound was deep down low and exotic up top. Again not apples vs apples but this is my car in the video:
My terrible point Im making is that if Remus can do this to the F90 for 1/3rd of Akra, Im hoping they can improve the G8X straight six as well to a better level.