Dual-Diagonal power assisted 4 wheel ventilated disc brakes, 4 channel anti-lock braking system.

Front Discs:
Ventilated 11.7 inches diameter, 28mm rotor thickness

Rear Discs:
Ventilated 11.9 inches diameter, 23 mm rotor thickness

Swept area:
Front: 221.1 Rear: 229.2

97 and after models:
Larger front and rear brake rotor diameters and rotor thickness. Front caliper pistons went from 40mm and 34mm to 40mm and 36mm.

Taken from NSX FAQ. Hope that helps.