Disclaimer: By no means am I an expert on turbos, lol.
But from what I have heard, there are rumors that float around that turbos give you better fuel economy because there's more air induction and therefore less fuel consumption is needed.
Personally, I think that's a load of crap. You might be able to get the same or a bit better if you're shifting at 2k, but honestly, why would you get a turbo if you're gonna be shifting like that?
I guess like with non-turbos, it probably depends a lot on how you drive it.
But, like I said, I really don't know much about turbos and could be absolutely 100% wrong, lol.