Need Some Help

Geoff-AU

The Nismo is not faster (straight line). It has a bit more power and a bit more weight, those factors cancel each other out (and are small differences anyway).

The Nismo may be quicker around a track due to the stiffer suspension and chassis bracing.

TL;DR: If you want a track warrior, buy a Nismo. If you want a road warrior, buy standard.

Unless you're talking about twin turboing it and making it a GTR killer, a 370Z cannot be a sleeper.