Not trying to add fuel to the fire, but the opposite, to clarify a bit. Test numbers have to be taken for what they are, which means in what conditions they were performed. Of course Car & Driver and Motortrend know what they are doing, but they certainly test differently than Edmunds, who obtained a 5.3 (5.8 with traction control enabled) seconds time from 0 - 60 mph with a Touring 6MT. Why the difference? It's actually a good read:
Edmund's 370Z track test
How Edmunds tests cars
A lot of the difference is to do with the 1-foot rollout (read the second article to understand the details). So without knowing exactly how Car & Driver and Motortrend, or anyone else has tested the car, it's impossible to compare numbers with another test and have reliable results.
By the way, I had no idea about any of this until a couple of days ago, when i saw the Edmunds results and thought "These guys have no idea how to test a car!". I kept reading and finally understood.