A 4X4 escort cosworth shell in OZ is a big ask, When i lived in the UK a fitted 4X4 running gear to a 2wd sierra sapphire shell not a lot of difference Mostly gearbox tunnel and 2 small semi circular cut outs in the front chassis beams. you will find it very difficult to import an escort cosworth shell into OZ, maybe even impossible, almost certainly very expensive. Good luck all the same, and i will watch this post to see how you get on.