I recall Nissan doing an under-the-radar weight distribution experiment in the mid/late 1990's in an effort to find "the perfect balance" for front engine/rear drive platforms. The result was 52% front and 48% rear was the ideal balance. This makes sense to me based on my track experience when you start exiting the corner, you end up having most of your weight on the outside rear, followed by the outside front, etc. A weight distribution like Porsche yields a pendulum effect by nature, a front-biased distribution [like a Mustang] results in not enough rear weight transfer and you can't get enough traction, and then a front-driver weight distribution...well that's a whole different ballgame since the drive wheels are up front.
While the 370Z's published 54/46 split isn't "ideal", it's really close. Once you take a seat in the car and fill the gas tank, it'll be pretty close to ideal most likely. The spec sheet doesn't always tell the whole story; I think we should wait until we see some production car corner weight results before bashing our heads over a really close to ideal spec.
Cheers,
Ryan