You might want to re-think the front only upgrade.
The 350Z is heavily biased to the rear for increased stability under heavy braking.
One track event with hard braking and the rears will be gone. I had to drive to Dallas from Oklahoma with metal to metal in the rear to fully understand this.
On another note - can you get by without spending thousands?
My 350Z is an enthusiest automatic. It was driven by my daughter, her boyfriend and me at the ZCCA event on the big track at Willow Springs. Because the car was driven in full auto mode by the kids, there was no engine braking before I climbed in for my run.
3 back to back 20 minute or longer sessions with 5 minutes between.
I had no brake fade and ran as fast as any 350Z on the track in group 3, where passing was allowed, that was not a race car or supercharged.
I used Castrol Synthetic brake fluid - cheap for a high temp fluid, Hawk HP plus pads and slotted/dimpled rotors.
I don't doubt bigger brakes would allow me to run deaper into the corners. But the traffic in front of me was always braking too early anyway.
When I do go with the big brake upgrade it will be with the Wilwoods from
http://www.350zbrakes.com/
I used Wilwoods on a full race Z before and you can't beat that 1.25 inch thick rotor.