I swear by Quietcar.net. They have a visco-elastic membrane you spray on. The difference is amazing and I thought it was worth the cost. Its a lot of labor to get the seats and carpet out to spray the floors, but it deadens the sound. The insides of your doors make the most noise. Theyre like speaker boxes for road noise, so start with them and see what you think, whether or not you need more or if youre satisfied. Also if you use STUFF expanding foam in frame voids, you have a major reduction in noise as well. The weight is not noticeable, and alot of high end manufacturers do this at the factory to deaden road noise. In the edge there is a space formed sort of like a boxed frame. If you have a tow hitch you can see where its attached to your vehicle. All that hollow space? Just another place for vibration to be amplified. if you fill in all the little spaces, spray the insides of your door panels, youre edge will be as silent as a the inside of a coffin.
I dont have any interest in quietcar, but since using it on my 94 toyota MR2 (very loud interior) Ive been a true believer. I did only what i outlined above and my MR2 is as quiet as any sedan even with its low profile tires.