They tried to correct the nervous feel of the 3 door Cosworth on the Sapphires so I assume that fitting the 3 door ARB will cause the Sapphire to feel like the 3 door.

I am pretty sure that most of the mounting points are standard Sierra and that components only differed between models. The only shell specific to the Cosworth was the Escort. Even the 4x4 Sapphire Cosworth shared the shell with the other 4x4 Sierras.

4x4 Sierras and Esocts used the large diameter single piston calipers and the RWD cars used the 4 pot calipers.