FordRallyeSport

Hey all... Looking for some help on this one.. I have a 2wd saph cossie.. A bought it as a breaker and was goin to re-shell it/ use for another project. I have just bought a saph 4wd motorsport shell with no sunroof. My dilema is that im not too sure what is the same and what i can use or not use from the 2wd saph. I know things like the crossmember, gearbox, sump etc is different. Would it just be easier to buy all the 4wd running gear and just use the engine. I was wondering if anyone would be able to definetively outline the main differences.
Big ask i know!!lol as its probably a lot..