IF you are referring to the part under the package tray-DON'T. Honda is not known for wasting materials. Second-the fact it is there has little inpact on the performance of your stereo. How much Dynamat-seems you do not understand that it is NOT necessary to cover every bit of the car's interior for the stuff to work. Not only that-it gets very heavy and horribly expensive very quickly. Read the Dynamat and Cascade websites before doing the project.