has anyone used this stuff from jaycar in there boot trying to eliminate road and diff noise, allready have dynamat in the boot allready but thats only for resonance and doesnt block sound ... ive heard some carpet underlay can be good for noise blocking but has issues with absorbing moisture https://www.jaycar.com.au/heavy-duty-sound-barrier-damping-material-improved/p/AX3680
Yeah, because the vibrations are being transmitted to the body so efficiently you'll have a hard time dulling it with underlay as the whole car is acting like a speaker. Your money would probably be better spent on some rubber bushes. The material you're looking at will be fine in terms of water though, it's synthetic and hard mineral so wont be absorbing atmospheric moisture like a natural fabric would. It is still fibrous though so if you spill something in it or water enters the car from the undercarriage or wheel arches it will hold it and need to be pulled apart to dry.
