Has anyone had an promising mpg figures adding a turbo (preferably an STS remote system) to a 5.7 Vortec or even an older engine setup?

Im looking to purchase a new engine and wanted to add some boost while doing so. The stock 5.7 "R" Vortec engine can without a doubt pull the suv but I would love better gas mileage. So does anyone have an real world figures from aftermarket setups?
5 answers 5