just a word to the wise.. If you buy a used spoiler make sure it has the mounting brackets.. Because if it doesn't you'll have to order them through Lexus and that'll take a couple days.. The brackets aren't expensive or anything, but it's just inconvenient if you want to have it installed the day you get it..
Also, Drop'dLex is right.. Around $125. is a fair price for a used..
Also, the only real difference between the factory spoiler and a replica is that the factory spoiler sits higher.. Like for example, if you were to stand behind 2 GS, the one on the left has the factory spoiler and the right has the replica.. The spoiler on the left would have 4.5" gap between the spoiler and the truck whereas the spoiler on the right would only 2.5-3" gap.. Understand??