A c16 again would be best suited to a midrace engine, a City16 may be a little more suited, however, I had a Hebo sport cylinder on my old setup and a Yasuni r was a fantastic exhaust as many people will tell you..
Just because the exhausts are "higher" up the range, doesnt mean they are any better for that setup, they are all made very differently from one another for the three different setups, street, midrace and highend.