I found this video the other day. It was discussed on a 350Z forum I still visit every now and then. Anyway, its a show called Forum Wars where they basically take car forums and stack them up against each other in a series of performance tests. According to the discussion, the original plan was to stack a 370Z against the GT but it didn't pan out, so they used a 350Z instead.
YouTube - Forum Wars - Episode 1 - 2008 Shelby GT VS 2003 Nissan 350Z