I dun know, if you guys already determined this, but I was to lazy to read all the posts, it's not a Camaro, the side mirrors dont stick out far enough, it's to high in the back and to high in the front to be a NSX, so if you look at the front and the back it kinda curves like a R33, or a R34, the back is high enough and the side mirriors are in the same place.
Now it also is a give away from the ammounto f Skylines in the game and at the start what do we see as the main car? A Skyline and what is Kazunori Yamauchi favorite car company? Nissan, the cover wasn't changed from the Japanese version I don't think and well yea, it's either a R34 or a R33.