Don’t rule out a mechanical problem with the vehicle. If you are noticing an irritating level of road noise, you may have a tire, wheel bearing, or suspension problem. Wheel bearings are especially notorious for this, starting out subtle and gradually creeping up in volume till it sounds like you are driving on rumble strips all the time. I just replaced a bad wheel bearing in my 17 year old minivan, which had a really annoying amount of cabin noise at speeds above 20 mph due to the bad wheel bearing. Now it’s quiet as a tomb until wind noise starts creeping in around 75 mph. Unless you know the vehicle has been this way since new, there may be a mechanical problem causing your intolerable road noise, and this is a certainty if the car didn’t used to be this way and suddenly is. I suggest taking the car to a trusted repair shop to rule out a tire, wheel bearing, or chassis problem before gutting the interior and adding more insulation to try to cover up what may be a symptom of a dangerous problem. A good mechanic will know if this level of noise is normal or if a mechanical problem is causing the noise.