More info would definately help. I assume for your username you have a 2000 EJ9?
Do you want a loud, or quiet exhaust?
Even when you've answered that, there's still personal taste to take into account. What style exhaust do you like? Personally I don't like the look of most of the Tanabe range.
Try having a look around and doing your own research, and then when you have narrowed the selection down to those you like, perhaps ask which will give the best gains. And even then, the difference will be minimal between most cat back exhausts.