Sorry but that is incredibly cool 
I wonder if this would work with vehicles, we could make Stealth Tanks and cool stuff.
Hmmm... Would it be possible to make a vehicle that, after the spacebar is pressed, changes to a different model that looks exactly the same but completely transparent?
Of course, the driver wouldn't be invisible, rendering it useless, but that might be worked around with a command or item.
That would be possible, and the driver could be rendered invisible as well but removing all his body parts when the Stealth Mode is activated.
I've actually been thinking the same thing for invisibility (replacing the model with a transparent one that is).
Side note
I found out something about the gun,
only parts of it that are included in Animation sequences appear funky, the rest is 100% invisible.