Hi andrew,
I would look at the younger more gullible driver 17-25 is where the real money is at the moment. You need to follow the example of other car modifying companies and aim at the "thick" end of the market to put it politely. Go for the Saxo, Clio, Nova, Micra drivers to name a few - the ones that will buy anything at any cost if you tell them it will give them better performance. Then you need to get some good PR and marketing going, cleverly worded adverts to entice people to buy your product, really make them believe it does anything you claim. Appeal to drivers that can't get insured on anything above a 1.2 and tell them your product is brilliant, they will grab it. That's the basis on which some exhausts are sold when they do nothing for performance, also induction kits that reduce the engines efficiency by sucking hot air in. Then you get many other items sold in a similar fashion. Pick up a car magazine, look at which products are aimed at which people and just follow their example and you will be laughing all the way to the bank. You will be happy and so will the boy racers. There you go, a quick lesson in market research, advertising and sales - works every time! Best of luck, just don't feel too guilty.