Sonus Faber Nove II or III

I currently have the Sonus Faber Sonetto V's paired w a Moon 330a and Lumin T2 streamer. I absolutely love and enjoy the Sonetto's. However,  I can't get rid of upgraditis. My dealer is offering a trade in deal, so I'm looking at the Nova II and III. All they have is the Nova V's to audition. I'm currently in an apartment which does limit my volume to an extent. I've read varying answers as to how much more depth output the III's have. I listen to most forms of music expect country and new hip hop. Metal and jazz are what I listen to most. 

Any help with comparison would be appreciated.