Its unmistakable form continues to live on in the very capable Z4

Whenever I hear these four words, usually blurted out by somebody I've just met at a noisy social occasion, my eyes glaze over and I begin to panic.

For while most normal people will casually mouth "Audi R8" or "Ferrari F430", I'll just stand there with a face full of teeth, desperately trying to come up with a vaguely acceptable answer. You see, being a motoring journalist who on any given day holds the keys to the latest automotive pinup, I've developed a taste for classics; in other words, cars that you don't see roaming our streets 24/7. The rare. The strange. The unattainable.

The 1955 BMW 507 Roadster, for instance, is a perfect example. It's not new; it's not particularly fast and - to patrons of your average Joburg watering hole - neither is it especially well known. But in a world filled with Bugatti Veyrons and Ariel Atoms, this comparatively antiquated machine offers something that titanium and carbon fibre cannot: soul.

The trouble is, though, the amount of rationalisation involved in explaining why this '50s relic is at the top of my rankings usually leads to awkward silences, judgmental eyes, sarcastic sniggers or all of the above.

So in order to get around this most painful process I've learnt to change or adapt my choice of car to suit any given social occasion and, more importantly, the type of personality it happens to be attracting.

Sitting around at the Baron and Chav in the marbled bowels of the northern suburbs, for example, I'll no doubt plumb for something up-market, fast and - I stress this - über-modern. For even though my beloved 507 Roadster wears the socially acceptable BMW roundel and sports a fashionable retractable roof, its lack of xenon headlamps and a proper Harman/Kardon sound system will no doubt leave Mr and Mrs Dainfern wringing their manicured hands in disgust.

However, if I puffed out my chest and waxed lyrical about the all-wheeled brilliance of the Audi RS4 or how the new Jaguar XKR is just as quick as an Aston, and pulls more chicks for the money, then there's a good chance they'll be including me in their next round of Peronis.

Conversely, while being safe bets in and around the Sandton area, the RS4 and XKR lose their kudos as you start slipping towards the less affluent south. You see, for some reason, and I'm yet to find out why, premium brand vehicles, like fashion, just don't hit it off with wearers of the blue collar. In fact, even if they could afford them, or won the lottery, this sect of petrolheads would probably still choose to ride around in modified Honda Civics rather than one of the latest German imports.

No, sticking it to the northerners in something reasonably cheap and classless is the order of the day. So to avoid any undue animosity when visiting the other side of the tracks, I always find it best to mention names like Nissan Skyline R32, Opel Superboss or Subaru Impreza STI.

Once again, missing the much- heralded body accessories that contribute towards these vehicles' appeal - ironing-board spoilers, drug-dealer wheels, under-car lighting, faux diffusers - the sleek, understated lines of the BMW 507 hold zero appeal. Its lack of performance, especially considering its lofty price-tag (F1's Bernie Ecclestone recently sold his for just under ?1000000), also counts against it and, barely able to crack 220km/h, I'd be laughed out of Boksburg for my taste in cars quicker than you can say "nitrous oxide".

Needless to say the environmentalists hate my beloved BMW too. Yes, they understand that a sports car is at the top of my all-time favourite list but they don't see why it has to be a 54-year-old with diabolical fuel economy and above average Co² emissions.

Therefore, the easiest way to avoid yet another lecture about the affects of global warming, Al Gore and drowning polar bears is to say that all your motoring dreams and aspirations lie with the Tesla Roadster.

Of course, the reality that this machine is useless in a country powered by Eskom and not very eco-friendly to produce is irrelevant; the fact that it uses no petrol and huffs no fumes will earn you massive brownie points with those who spend their weekends tagging birds on the Melville Koppies.

Unfortunately, no matter how necessary it may be at times, the more I string people along the more I think I should be spilling the beans on why the 507 does it for me. For unlike a lot of other classics, this one holds a great deal of cultural significance; the sort that I think people should know about.

The first sports car manufactured by BMW after World War Two, their design team specifically developed this svelte Roadster to tap into the glamorous US market to make the brand cool again. Artistically it succeeded and, thanks to its chrome bumpers, exaggerated gills and Corvette-like curves, this German was soon garaged by the likes of Ursula Andress and Elvis Presley.

The problem was, as you can deduce from its previous owners, the BMW 507 was astronomically expensive to buy, with only 251 being built and delivered once production ceased in 1959. Yet no matter how much of a commercial failure it might have been, its unmistakable form continues to live on in the Z4 - a car so capable it almost made me hurl when I thrashed it around the twisting roads of Spain in April.

But actually, come to think of it, the thought of explaining this brief history to some pink-shirted jock raging on hormones and beer is enough to silence my admiration for the 507 forever more. So what's my favourite car then? I guess it still ultimately depends on who's asking.