First of all I wouldn't buy anything from ebay that you want for looks lol. Do your research and be willing to put down a lot of cash for a nice looking wing, take a look at chassis mounted ones if you really wanna be a ricer so bad. But as for the hatch mounted, Apr makes a nice one, GTC-300 isn't bad.. Actually why tf am I even stating these, just go to this thread and you'll see them for yourself.
Official GT wings/spoilers thread
There's ricers for every jdm car, you could have just type "gt wing on 370z" and many posts would have popped up.