Quote from robt :

Personally id love it!!

For as long as it takes my friend. After 3 seconds you will hear nothing but a silence, just after one final *POP*.

Depends on what is waking you up the BRM/Formula Junior type sound is a high revving enigne sound. Whereas that Austin 7 was just painful to hear. Probably a hillclimb special so the driver only has to hear it working for 30 seconds