That's just the AAM short tails (resonated). HFCs will make it louder and sharper from what I've seen on the other Zs here in Denver, but the tone stays about the same.
Just the short tails though was loud enough that it annoyed the neighbors when I left the house at 6am, and I hate being "that guy". But what really sucked was the resonance in the car; at highway speeds the trunk area would buzz, the headliner would buzz. Hell, stuff inside the dash would buzz.
So I went back to the stock nismo exhaust until such time as I can justify a real four-digit cat-back solution that sounds better than stock, but isn't as boy racer about it.