You're better off looking at the Q60 red sport, not the 370z for comparison.I would leave it stock for baseline stuff at the track, maybe 3-6 mos, then really want first thing is a better sounding exhaust. That one video by Raiti's really shows the weak sound.
What has worked best on the 370Z for catback or turboback as far as sound and weight, durability? Ark, Powerhouse, ???