I have read several posts in different threads regarding the VDC system on the Z. Since I wasn't a 100% sure on how it worked myself I started doing some digging and here's what I found.
First off, the TCS and ABS/ABLS are independent safety functions of the Z. While VDC is "ON" these systems work together to help keep the car under control. See sections 2-14 and 5-25 threw 5-28 in your owners manual.
The following link explains how the VDC system works.
The Safety of Nissan’s Vehicle Dynamic Control System (VDC) Explained VictoriaNissanBlog.com
I also found this link helpful.
Nissan 370Z: Prices, Parts, Accessories, Photos, Specifications