Something about ICE... the car itself is also very important...i got a friend doing ICE shop he said car with loose part might cause lost of quality..when sound travel, hits on rattling metal parts, loost bolt or nuts, it might just lost some quality, because it already turn into some other energy ma...some better made car use multi layered glass for windows to sound proof...that is why soemtimes u will feel the sound quality is better in some cars...
JMO :P
JMO :P