[itronitron]

Cars seems like a good example because the quality manifests itself physically and is independent of how well an individual buyer perceives quality. Also, the buyer is directly responsible for long-term costs associated with their decision which isn't the case in currency exchange.

[baq]

you mustn't be talking about used cars which are perfect example of https://en.wikipedia.org/wiki/The_Market_for_Lemons where if it is impossible to tell what quality a particular good has the price goes down to the lowest common denominator so to say.