Does all this fancy ANR interfere with the pilot's ability to hear an early warning noises from the engine?
You might find it odd at first with the Bose (or any other ANR) how quite things become at first. It can be disconcerting until you are use to it. The high frequency noises become much clearer and you will hear components of the aircraft you have never heard before.
Could a low frequency noise be the first indication of engine or other problems and be suppresed. I suppose it is possible, but logically you might think high frequency noises are more likely or at least would be a component part.
What is the version of the Bose X needed for a C172...
Two jacks (a single jack is for the helis), non powered, leaving you only to decide if you want the helicoil cable or straight. Apparently straight is more popular and was the type I selected.