They would be legal in as much as you would actually be complying with the law because your not actually venting any gasses, but i'm sure you'd still get pinned for it because it has a trumpet hanging off the side of it and could be venting to the atmosphere. Try explaining to the cops that "its got a trumpet but i never have it set to VTA, its always set to fully plumb back into the system".
i dont think the 'i take the car to the track and flick to VTA' would be good enough either i spose.
