The difference is like night and day. You don't even have to install it all over the door. I put two layers of Dynamat Xtreme each about 12'' x 16'' spread out horizontally on the bottom front corner of each door. The bass kicks and nothing rattles. 8)
Also take the round sections you cut out for the speakers and push them trough the speaker whole and stick them on the inside of the outermost panel, behing the brace so that they're right behind your speakers.
Play around with it after you installed those pieces put the door back on and listen for ratttles. If you find any take the panel off and apply some more in in strips till you get perfect bass resonance.
Use a song with alot of deep sustained bass for your tests.