Theres no doubt that it works, but if you crush or bend it too much, you might not be able to go back. It wont always double your boost, you can control how much you want depending on how far you crush/bend it.
Its just not the way to do things. I know that on S4's some people have crushed the stock fuel pressure regulator to go from 4bar to 5bar pretty accurately. Again, not the right way to do things, you might end up screwing something up.
You're basically breaking something in a way that it happens to not work correctly in your favor.