Hey Justin,
You have concerns about Z32 rotor weight? It's quite heavy compared to stock. If you check out my website:
http://www.conecrazy.com/project-g20/brakes.html
Don't make fun of me because of the red GABs
Because of them I bought a powdercoating rig and did them in gunmetal grey. I just bought a digicam so I'll be updating the pictures.
Whatever weight I gained from moving to heavier rotors were lost by going from 17" wheels to 16" wheels.
17x7 MASitaly MGR with Yoko A520 = 42lbs
16x7 GAB Sports with Pirelli P7000 = 30lbs
I have a couple of ideas to keep weight down:
1) There are a few used Z32 Brembo upgrade kits floating about in the various Z forums. My friend picked some up for about $1400 for a used Brembo bigass brake kit. Even though the rotors were much larger than stock Z32 rotors, they were much lighter. Problem is, you'll need to shave the rotor's OD
2) If you wanted to keep the brake upgrade under $1000, get the Z32 calipers and get custom two piece rotors. Since it's a custom rotor you can specify the OD
After doing any front brake upgrade, I suggest you get a proportioning valve to adjust brake bias. One more thing, the Z32 brake upgrade did not require upgrading of the brake master cylinder.
Al Abadilla
www.conecrazy.com
ICQ 1372065