sound deadening undercoating can help reduce noise and vibration, and it can also help improve the insulation of the car. This can result in a more comfortable ride and can also help save on fuel costs since the car will be using less energy to stay warm or cool. However, sound deadening can also be quite expensive, so it’s important to weigh the pros and cons before making a decision. Overall, though, adding sound deadening is usually worth it, especially if you do a lot of driving in urban areas or on highways.