Why? I've driven a '96 NSX and an '01 Z06. I believe the Z06 handles signifigantly better.
If you'd like some backup on that, look here:
http://www.roadandtrack.com/article....ber=1&preview=
This is the '01 Z06. It beats every car except for the 360 on this course. It lost by under a second to the 360. The '02 Z06 has 20 more Hp and is lighter, which will give it a slight advantage (very slight) over the current 360 on many courses.
But the question of whether it handles better than the NSX? You decide.