The likelyhood of a vacuum leak on a new vehicle is pretty slim.  Why
bother with it at all?  Just drive it or if you really need to see the
vacuum condition, buy a vacuum gauge...

If you were planning on tapping a hole, I would think you could try it
out and just put a screw in the hole if it started acting strangely.
Maybe someone could speak to the computer side of things.  I would
think the computer would compensate for a vacuum leak but you really
wouldn't have to worry about it screwing with the computer as much as
the engine by the computer making it over compensate.

I guess the question is how big a leak does the whistle cause? Everytime you
activated the whistle the computer would see a lean condition and try to
compensate i.e.. add fuel by opening the injectors. Then when you turned off
the whistle the computer would see a rich condition and again try to
compensate by closing the injectors. A big leak would cause a bigger lean
condition and bigger swing between lean and rich. This could throw a code it
could reduce the life of the catalytic converter. It all depends on how much
and how often.