SophiaZ

I bought the Nismo Z exhaust from the dealership months ago and someone told me that the Nismo exhaust I ordered isn't the same as the one off the factory Nismo Z. They said the factory came with TRUE dual exhaust. But while I was at the dealership today, I looked underneath the Nismo and found out that it has a single muffler with smaller dual tips (maybe with sometime of resonator?) I asked one of the parts guys and he explained what the differences were..and he was saying some crap about how the Nismo parts are actually better than whats found on the stock Nismo. He also said that the Nismo was mainly built for appearance. I do not understand this whole thing since the Nismo has an extra 18 hp! Can someone please explain! I think the dealer was backwards. I just want to know why my NISMO exhaust looks different from the one on the REAL 370z NISMO!