I'm doing the same thing to my S2 next year, the 1 think that is an issue is the rear turrets, they need to be moved back. The Escort shocks sit in line with the middle of the of the back wheel where as they bolt to the hub, on a Cossie they sit behind the wishbone/swinging arm.

Have a llok here http://www.rsbible.co.uk/ Near the bottom there are 3 pics which will help make more sence.

I'm not sure if i'm going to use the Escort inner front wings or sierra yet.
Get some pics up when you do yours.