The trouble is that with this kind of questioning you end up with misleading figures. For instance, I don't think that age is as relevant to the question of exhaust choice as money is, and you'll more than likely find that the younger folks with less disposable income will go for the cheaper exhausts i.e. Scorpion or K1, but the older folks with more money will go for the Nismo or Milltek. It still works though if you remove the age from the equation altogether and just look at the money side of things. However, asking people to state how much money they earn and what exhaust they've got is parallel is likely to go down as well as a £5 hooker