tajones

A mate of mine is thinking of buying a mk7 escort and doing a cossie conversion. I've seen bodykits for sale for the looks but he wants to go the whole hog. He's got a 3 door sierra cos and wants to put the engine in the escort, along with 4x4 running gear. I've told him it won't just fit straight in because the escort cosworth uses sirra floorpan which is longer than the standard escort one. But he says he knows someone who has done this and all the suspension etc went in. The only thing he said to do was put a tunnel in. Can someone put me right on this so i can tell him he's wasting his time.
Don't know why he doesn't just buy an escort cossie shell they're cheap enough.