I'm not sure if the HR equipped Z's are the same as the DE's, but I'd avoid the base model so you could at least get cruise control. A side benefit of having cruise control is that
UpRev's Osiris tuning software lets you switch tuning maps with the cruise controls.

VDC (Vehicle Dynamics Control) is nice if you have to drive in crappy weather (think of a smarter version of TCS - Traction Control System) and like the safety net of the car making some corrections if things get too hairy. I rarely have mine kick on in normal driving, and there's always the option of shutting it off, but not
completely - it's always there in the background - just harder to get it to "take control" when it's turned off.
You'll eventually want to replace the diff unit anyway, so if you're going to go with a base the saving may actually end up helping finance what could be your first modification. I'd actually look around for a track or grand touring trim so you could get the Brembo brakes. Unless the price of the car is astronomical it's worth getting a Brembo equipped model as most decent aftermarket brake setups for the Z are pricey. Upgraded pads and rotors for the Brembo calipers are plentiful, while good/great pads & rotors for the standard calipers can take some searching.