Just thought I'd ad my input.
If your going to purchase the adaptor plates for the S1 280zx rear disk conversion.
Please bring along your caliper and check if the holes line up.
My S1 280zx calipers had about 0.5mm off on both bolts in comparison to the bracket.
Apparently there is a slight difference in bolt configurations for varying S1 280zx calipers.
had the same problem bought them back in and ha made a new set for me