There are tons of threads on this, so you should really use the search feature as a new member. Here are a couple threads to look at, but feel free to do your own searching:
370Z Exhaust Sound Clip data base
Best Exhaust?
Which exhausts sound the best? Owner preference?
But really, no one can tell you which exhaust you should buy, because what sounds good to you may not sound good to others and vice versa. Hope that helps.