Hi all I would like some help and info if poss please

Right I've got a focus mk1 1.8 zetec and I wanted to fit a turbo I read some were that the fiesta 1.8rs turbo fits straight in is this right or not? If not can I use the head and the turbo from that and fit to mine is it possible or not last thing are power boost valves any good??
Any help would be great thanks