The 370z does feel a bit different above 5K. The valvetrain isn't the smoothest as many have noted, and the speed is very deceptive: you don't feel like you are going faster but you really are.
I think this is mostly attributed in my case to the very good torque off the line and how tractable the engine is in almost any gear. I have had two previous small displacement engines which are soft down low, then very linear once on boost (both turbo 4's).
Previous NA track/street car had a high strung 4 that was linear with a tad more pull above 5500 so you felt that (and still soft below 2000).
We also have a G35 sedan whose power delivery is quite different and not nearly as violently delivered as the Z.
Coming from the Z32 TT, the 370 is going to take some getting used to IMHO
- b