as stated before, most any ypipe will do you fine. Though I didnt like their internet sales guy back in the day, UTR has a solid one.

 

Y-pipes will provide a performance benefit throughout the rev range on any G35 Coupe/Sedan, 350Z, etc.

The stock rear y-pipe has a very crude cast section which is a major restriction. Simply replacing that y-pipe makes the car much more efficient. Without replacing the y-pipe, most of the mufflers/exhaust systems out there will not show any improvements.

Generally, what we've found with testing is that:

exhaust with stock y-pipe = 0-2whp
Y-Pipe with stock exhaust = 7whp
Y-Pipe with Aftermarket exhaust = 9-14whp

It's arguably the more important piece to replace if doing exhaust modifications.

This our y-pipe:

 

I can't find anything about this product on your website. How much does a tanabe y pipe cost?

 

There was a noticeable difference in sound - deeper more throatier - when I had my fuji Y-pipe put on to compliment my Fuji legalis exhaust. Performance difference . . . I'm sure there was but I can't feel it. No worries, I still love my Fujitsubo.