Watch this sequence (it starts in 1994, and ends today):
Porsche 944, BMW E28 M535i, Porsche 944, Lotus Excel SE, Porsche 911 Targa, Porsche 911/964, Mazda MX5, BMW Z4 3.0si
The only time that I have ever had any negative response from other motorists was in the Mazda, when other drivers just seemed to get in its way, and I heard some "hairdresser" comments. Otherwise, these cars just seem to clear the way ahead of them, with the E28 being the best*. The best roadside comments by far were for the 964, but the Z4 is not far behind. Maybe one time out of four, when I park the car in my local town, someone makes a comment about it, and all these comments are favourable.
I live in North Wales, in a place that is quite well-off, but people do not seem to buy "flashy" cars, so there are <i>very</i> few cars here that are not just run-of-the-mill boxes, so something like a Zed, a Lotus or a Porsche is a surprise, that lots of people seem to like.
So, here, the perception of my Z4 is entirely positive, and it has started many conversations with passers-by, all of which have been pleasant.
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* My partner has a blue E46 325ti Compact; it is quite a mean-looking car, and has Xenon headlamps. Like me, she always drives with dipped-beam lamps on. Her car can clear slow traffic from the outside lane like a snowplough! I can only think that people see the blue car and the blue tinge to the dip-beams and think the polis is coming.