Sprint to Regular

Is there a way to change an unlocked Sprint S6 into a regular S6 so I can use the regular ROMs?

How can you tell if it's charging "quickly" vs "regular" AC?

I've seen a picture somewhere that shows the phone displaying "charging rapidly" at the bottom of the lock screen. I think it was on droid life. I'm plugged in with the included charger & cable and it only says simply "charging"... Is something wrong, am I missing something, anyone know?

Found it, here's the picture I'm referring to from droid life:

Regular S5 vs S5+ (G901F model)

So I mistakenly bought the S5+ (G901F) from a seller thinking its the regular S5. I just want to know if there is any significant difference in battery life between the 2 models?