What's The Most Distinctive Sounding Car?

Some cars sound like washing machines. Some cars sound so distinctive, you can know they're coming five blocks away.

If I'm walking down the street and I hear a particular raspy, low roar coming up from behind me, I know an air-cooled 911 is about to drive past. I don't even have to look.

Is there a kind of car that's even more recognizable just by its engine noise?

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