I would say he is correct. Straight from the factory the do what they can to minimize road noise. Ussually there is quite a bit of insulation on the floor of the trunk and also near the back panel or seat in the trunk also. They do have a think layer under the rear deck. All I did was cut a rectangle in the rear deck and then custome made a panel with some matching grille cloth. Helped with the bass and also helped with distortion of the rear speakers.