@speedbreeder, yes you are right. The 1992/1993 model had 280mm discs. The early models up to the change over year which was 1992 had smaller discs. If you dont believe me phone any nissan dealer and ask them.
The Z32 also had 280 discs but better calipers. They are almost the same as the s14 brakes but they are made of a lighter metal. So technicaly the breaking is the same but the heat resistance and weight differs.
Back to the 350z Calipers...
They wont be that expensive since there are like 4 wrote off 350's at every scrapyard. The brake pads will be about the same price as what we pay for and the "minimal" mods done to fit them will be worth the while.
I prefer a car with better breaks than a moerse engine! Give me any track and i will show you how I can beat you just by out braking you.
I proved that theory in my golf, my mates had golf pushing out 150kw where my NA 1.8 only had 94kw and I would kick their arses in every corner and then they cant get back infront of me.
Ask Mario he will tell you lots bout those stock cars and the problems they had. Those guys really abuse their cars and they stick to what is working.