Sometimes I think the 370z is one of the better looking cars made in the last 15 years...
There's something nearly exotic about its proportions I think - from the side
But then you see it from the back and you just think ok...whaaaat?
More than just the proportions, I always thought the 370z detailing was incredibly refined. Like the way a pillar, door, fender, and hood come together is very well resolved, and just overall care with how various elements are terminated or intersect. It looks like a high quality product...even if they obviously cut costs in the interior.
Edit:
Another interpretation of what the 400z may look like, based on the silhouette images:
I think I like it...but not 100% convinced. When you brighten the silhouette...it does start to get a little pudgy. But that's just how cars are now I suppose.