well, you're not going to be able to get the detail out of your armor like you would like. it's very very hard to work with, and the end result would LOOK the same if you were a master craftsman. In most cases, plastic will look better because of it's ease of working.
I don't want to discourage you, but that may be a little too ambitious. There's a reason they use plastic in movies and theater props. Its mostly because it looks better, and is cheaper.