4 piston brembos, Master cylinder, proportioning valve confusion.

A lotta folks installed Wilwood systems planning to use stock/ralley/their wheels. There were interference issues causing them to unexpectedly buy new wheels and tires. Be aware .
To be legal and safe you do need an emergency, so I'm glad you are persuing it.
Personally I think the "cobra style" rear caliper DrDiff offers, is very similar, and a little more cost effective, no decal?
But I havent checked recently .