A polish guy was selling cheap fibreglass kits on ebay. They're cheap for a reason.. they're CRAP! Aside from the fact that fibreglass is one of the nastiest materials on the planet to work with, they come with no fixings and you have to rely on your bodyshop to practically bond and rivet the whole thing together.. god help you if you ever want to get it off.
Recently fitted one to a rover 200, we basically stripped it completely, re-finished it and had to cut/bend it to the shape of the car. 2 tubes of Sikaflex, 2 cans of expandafoam, LOTS of rivets and filler later.. and it just about stuck to the car.