No movement detector will detect a 'flying brick'
A dualtec needs both technologys to activate not just the mic etc.
If you had a sensor that sensitive it would be going off all the time. That's fine when all its doing is turning a light on, not so much for an intruder alarm.
You need to protect the perimeter as above ie glass break (I hate them) vibration (not advisable on a front high street window, or foil.
Id also politely suggest you don't keep saying 'this is simple / plug and play etc' when talking to the people you want advice from and know more than you or you wouldn't be asking.