this is some the info i found out from a site
http://importnut.net/300zxbrakeswap.htm
The following is a comparison of some different Z32 300ZX brake calipers.
The "26mm Aluminum" calipers were used ONLY on 1990 non-turbos. They used a 280mm x 26mm rotor.
The "30mm Aluminum" calipers were used on 1990 Twin-turbos and ALL 1991-1992.5 300ZX's (both turbo and non-turbo alike). They used a 280mm x 30mm rotor.
The "30mm Iron" calipers were used on ALL 1992.5-1996 300ZX's (both turbo and non-turbo alike). They also used the 280mm x 30mm rotor.
and from
http://vlane.com/specification...tions
Front Brake Rotor Diam x Thickness (in) 11.02 x 0.87so for the guy talking about it being 18mm....wrong...it would be .87 inches = 22.09800 millimeters
)))))(((((( as for the brembo's dont know if they are better or worse off but i will find out cause i am going to get the 30mm aluminum 300zx setup...super cheap...the only downside is that the rotor needs to be re drilled unless you are running 5 lug. and not the stock s13 4x114.3