First of all if you know how to drive the NSX will kill a C5 on a track. It could even beat a ZO6 if the driver is super good. Dont believe me? Go to Racingflix.com, register, download a video called JDM vs. Supercars. The C5 came way last. It lost to a NSX, Evo, GTR, Ferrari, and a Porsche. The C5 hardtop is faster in a straight line.

Not sure how fast the NSX is but here are the Corvette stats.
C5 conv. 4.5/13.1@111
The coupe is even faster and the ZO6 is faster than the coupe.

The NSX isnt heavier. Well at least the Zanardi Edition.
ZE NSX: 3165 lbs.
Corvette hardtop: 3300 lbs.

Corvette Hardtop: .91 G's
ZE NSX: .93 G's

The NSX is reliable but so is the Corvette.

The NSX is handbuilt.