louisville13

So I have been looking to buy my first z. I finally found a nice one that I like, it is an 05 track edition 350z. The ad says 350z track edition pre-nismo and says that the car has some nismo parts on it. Heres the ad: (http://louisville.craigslist.org/cto/4982976594.html)

I think I am going to buy the car because I really like it and it has low miles. I was just wondering if all these nismo parts came factory because I haven't been able to find another car like it. Thank you.

edit* Also is the increase in hp just from the nismo parts being put on the car?