I think you missed the point I was making - whether or not they know anything about cars is beside the point, it's just the very fact that they brought it up illustrates how it is something which goes through people's heads.
I'm not saying I think Top Gear presenters word on the automotive industry is gospel.
I'm not even saying that I agree with the viewpoint they highlighted.
All I'm saying is that they highlighted the perception that some people "rightly or wrongly" have about the Boxster.