I had the same problem with my Matrix S model. I felt that the highway road noise was very loud. After doing some research I applied sound deadening material to all of the doors and the hatchback. The difference was UNBELIEVABLE. The car is as quiet as a Lexus LS430. It completely reduced the noise. I have enough material to do the floorboard and the ceiling, but that will have to wait to another weekend. I posted a thread detailing how I did it. I would highly recommend this upgrade. It is like driving a completely different car.
How to Sound Proof Doors
I was the best $ 240 I ever spent!!
