Hi George,
Motordyne TDX V2 exhaust + Motordyne ART pipes would be amazing in terms of sound, but a bit loud.
ARK + ARK R-Spec pipes would also sound awesome, here is how it sounded on my car:
Invidia Gemini + Berk HFC would another options.
All these and many other systems are available on our online shop here: http://www.torqen.uk/84-exhaust-systems
Amuse R1 STTI Titanium would be the ultimate, have a look here: http://www.350z-uk.com/topic/96473-for-sale-rare-370z-amuse-r1-titan-rs-silent-stti-exhaust-system/