I have experience with Dynamat in regards to car audio systems. Dynatmat does work, and is fairly simple to install on large surface areas, however a product by Cascade Audio is better, as dynamat peels easier and does not deaden vibration as well. They make a small aerosol can for tight nooks and crannys that deadens sound also, this might work for specific door areas, however I think you are looking for an overall lower db level. Have you checked all your seals? Is it wind noise? vs Road noise? Engine noise? Type of Tires?