“That's not where the turbo is supposed to go.”
This is a very strange idea. As you can tell from the title, the video is of a Chevy S10 with an LS1 under the hood and a turbocharger in the bed. While it's true that a setup like this would save you the trouble of finding room under the hood, it does seem like it would end up being a lot more work in the long run. Although it's obviously hard to say, because we've never seen such a thing before. Of course, the owner seems to enjoy it, so more power to him.
We also get a bit of footage shot from inside the bed while the truck is driving, and it does indeed sound pretty terrific. So, again, we can't really fault him.