Granted I'm not a Business major or anything but I would think if you wanted to pick up business you should try to get into the retail market. Send free samples to car audio shops and let them try it out. I live in a smaller town (approximately 40,000 people) and we have two car audio dealerships. Neither of them carry any sound dampening stuff. As many people as there are that read these forums or similar car audio forums I'm sure there are 3-4 times as many that don't and are unsure about which sound dampening to buy or even what it is or whether or not they need it. If you had car audio shops pointing it out to people and maybe suggesting it I'm sure you could get a lot more business your way. Right now you're just trying to get the people that are looking for the stuff but are trying to decide between the many different companies out there. These people have more than likely had previous experiences or maybe friends telling them what to buy. That only leaves you with a small margin of pepole that are new to the market or had a bad experience with their last dampener and are looking for a new product. If you make people more aware of the product and what it does and maybe make it a little more easily accessible, via car audio shops or the like, you get a lot more people in the market. Even if you only get 10% of the new market initially, those people will spread the word and then they will spread it etc etc.
Maybe you do this already or maybe my vision is skewed by the fact I live in a smaller town but this is how I would do it if I were you. Good luck, and if I do end up buying dampening down the road I'll make sure it's from you =)