Just dropping this here :
"FC3S / FD3S early caliper diversion Stallion 5 hole car only
For A183A (GSR-V only), A184A/A187A
Stallion 5-hole hub and disc are required when installing to A183A (4-hole wheel) and A175A (with I/C)."
In the past I came across an adapter bracket for what I thought was a bracket for a Nissan 300zx caliper, but after ordered I found it to be for a Skyline caliper (which are too expensive to bother using in the US).
RX7 calipers may be easier to come by.