Axelsc1, this is your seventh thread about exhausts. I understand English is not your first language, but that does not mean you cannot simply search for threads instead of posting new ones so constantly (and not just about exhausts after looking at your started threads).
ibtl, which is hopefully soon

sorry if this sounded harsh it was not meant to be

I like the sound of Nismo, Stillen, and Amuse.

I'm sorry, but I have to agree, I noticed all the other threads too...

I never do this for others, but here is a site I have used to help me study a lot of exhaust options. Pictures, videos, dyno charts (when available), and link to purchase are all on this site.

370Z Exhaust.com - Sound clips, photos + places to buy

Stillen
http://www.the370z.com/intake-exhaus...k-exhaust.html

Invidia
http://www.the370z.com/intake-exhaus...st-review.html
http://www.the370z.com/intake-exhaus...ssan-370z.html

Berk
http://www.the370z.com/intake-exhaus...ll-review.html

If there are other brands you are interested, do a search because a lot can be learned from other member's reviews. Search for these topics too:

-HFC/Test Pipe
-Magnaflow versus Invidia
-Best tuning

-Ray

I thought Berk had really high power gains if not the highest, their fitment is amazing. Fast intentions is popular and nice but I just don't like how they sit on the car, just my opinion.