A pack of Dynamat adds around 9kg to the car. Imagine if you use 3 pack for one car and that's not full coverage. Already 27kgs. One of my cars had almost 40kgs in and another only had 2 packs. Properly installed and placed, they sound (or lack of sound) almost similar.

For some areas, you just need to dampen the panels wit strategically placed dampeners and then use cotton liners or close cell foam pads to absorb the sound.