PORSCHE CARRERA GT

Are there any differences between a 2004 Carrera GT and a 2005? Were the MSRPs on both model years the same? Are there market value differences? I have asked these questions to CGT gurus and everyone gives me different answers. Some people tell me that only 200 cars are in the US while others tell me more than 2,500 were made. Still others tell me that there are only 656 documented cars in existence out of 1,200 and the balance have been totalled. I find limited edition cars like the CGT, Ford GT, Enzo, 288GTO, F40, and F50s really interesting and am very curious. I would greatly appreciate if Anyone who folllow limited edition cars and have facts can answer my curiousity. Even books and magazine articles have conflicting opinions.