I has noise killer spray on my doors and it helped when I added the dynamat super there was a huge difference, Even in the feel of the door closing and the thud it made. I recommed using both together if you can spare it (cost and weight) if weight is an issue then the spray if it is not then I would use the mat over the spray. the spray is great in hard to reach places and odd contours as well as doors where the door panel has to go back on over the mat.
My .02
Dan
