OP.The supporting mods you listed should improve everyday mileage. At least that's what Ive found, with basically the same mods on my car.
As for the Procharger, I can address that on my GT, as I have one. I have not noticed any decrease in mileage during normal driving conditions. other than a slight whine, I really don't think you will know its there until you get on it. And at that point, who really cares about gas mileage anyway.
2011 GT. Grabber Blue. Procharged. 3:73 manual.Billit LCA's. Corsa Extremes. GT 500 wheels. Racemaster DR's. T-56 Tremec. Dynotech DS . Centerforce DF. American Racing headers/high flow cats 560 rwhp.Donny Walsh tuned
2012 Pony Package. Race Red.3:31 automatic.BBK longtubes and catted X.FRPP Sport axlebacks. BBK throttle body. Dynotech DS. Brembo wheels and tires. Strut tower brace. Airraid CAI. Bama tuned.