Well, I feel SOME other drivers definitely react, in one way, or another.
There's the ones described earlier who try to be faster, or whatever (I've been passed by a Peugeot 206 right downtown saturday morning shopping village, flying over speedbumps because I was doing 50 - legal km/hour, which is fast enough for the circumstances!).
Any case, I'm wary of other drivers (especially from behind...). In fact, I try to constantly remind myself to be a "civil" driver because I don't want to attact "negative" publicity to Porsche! Admittedly, it doesn't always work out that way, with drivers driving in the left lane at 90 kph when the right lane is empty!
But there's also the other thing: I seem to notice that cars actually get out of the way when you approach them from behind, even though I wouldn't exactly be charging down on them! It seems a Porsche does get attention, and not always negative.
I remember when I myself did not have a Porsche car, I would often try to follow the Porsche, just to have a good look at it.
Might this have been perceived "negatively" by the Porsche driver? I wasn't trying to be "competitive", gosh no!!!
So, maybe there's no need to attribute "one" or "another" characteristic to other people's behavior... a lot is probably self infatuation!