had a look on thier site, and they suggest the following.....


SIERRA 2 RS 500 Cosworth 162 YBD (T31/T04) 05.87-'88, K27PR-ZU, IK27, VK27PR-Z11.

OR

SIERRA 2 RS Cosworth 150 N5A (YBB) (T03) 10.85-'89, K24PR-ZU, IK24, VK24PR-Z11.

Also, whats the difference between the power, and the "tough" ones?

Cheers
Mike