I sprayed this on my trunk and wow, it did its job. Just spray where you see holes and make sure that no wires run in those holes or its just going to cause a mess. I did about 3 nice heavy coats. I did dynamat extreme on the trunk floors and on the sides and no vibration or rattle problems. It really improved the sound of my system. *I only sprayed the trunk door, not the whole trunk itself*. I was just lazy to dynamat the trunk door. But it did its job very well eliminating the vibration and rattle from my spoiler. What do you expect, its from dynamat. I used approximately 3 bottles to do the job and wear clothes that you do not want to mess up because its shoots out from the nozzle kind of wild, and make sure to put newspapers around your window and trunk lining and any area you do not want the dynashield to splatter on. Two thumbs up for this product.