are the brakes calipers on the st170 are they the same as 2.0 rear brakes, ive just heard that if i can get the caliper carriers dust shields and discs i can convert my 250mm discs to 280mm, he said thats what the fiesta st boys are doing.
does anyone know if this is true

 

Yes the calipers are same on all focus(rears) includingte rs