To Minicobra1
I had a similiar setup on my 350z (Nismo exhaust with random tech cats). I also felt the Nismo really came to life with the addition of the cats and my other breathing mods (plenum spacer and pop-charger). I really liked it. It kept the stock tone but made it more aggresive under load. The 370z iteration seems to be the same way
To Bster
I remember the HKS exhaust for the 350z, I always liked how it looked a lot but the sound can get pretty raspy. It's still not bad though. That video sounds like he is running test pipes though. A lot more rasp than I remember.