You still could not say it was a Z-tune replica as there are a lot of other engine and interior goodies that make it up, besides, why would you want to run around telling people you have a "Z-tune replica".....
The only thing that is a Z-tune item, as stated, is the front bar, bonnet and guards, the skirts and pods are nismo items.
At the end of the day, it's just another front bar.
I don't think it looks bad just having the front bar, that said, i am partial to the whole kit, but if using just the front bar is the what you like, go for it, it's still a sexy front bar at that.