I think there's some confusion about terms here.
In terms of legality (as far as the realm of airsoft velocities are concerned):
An item resembling an existing firearm, that fires a .2g BB at a velocity less than 366 FPS, is called a "Replica Firearm", and is illegal for you to import.
If that same item fires a .2g BB at a velocity between 366 FPS and 500FPS, it is an "Unregulated Firearm", and is legal for import.
If that same item fires at an FPS greater than 500 FPS, it is a "Regulated Firearm", and is illegal for you to import (in simple airsoft terms).