I can tell you I just spent the last few weeks repairing my cervinis front bumper and sanding it down and it was a PITA. I have not put primer on it yet and due to the complexity of the bumper will not trust it to my self to paint. My bumper was also heavily pitted to had to take it down past the color in most places.
Depending on the condition of the paint on the stock bumpers will determin how much you have to sand. you may not need to go much into the clear and if thats the case then you will have less work than if you need to go deeper.
Not sure on the offer. fitment its the exact same car, ZX5 side skirts IIRC are longer than ZX3 so will need to make sure you are pulling from same model for the side skirts, front and rear bumper dont matter.
2001 ZX3 2.0L Zetec-
Hatch Nation #42
Going through Rebuild See "The TICK Build Thread" for details (http://www.focusfanatics.com/forum/showthread.php?t=289168&referrerid=62897)