narrowing originally started out as a specifically beetle thing. it was originally done to allow you to steer without the tyres catching the arches on very low cars, as it put the wheel into the tallest part of the wing, away from the curve of the arch, and the arch lip. look at the wing shape on a bug to see what i mean. it also had similar gains on split and bay vans too, as it moved the tyre away from the arch lip strengthening box section, and into a taller part of the arch below the seat.
it does have its practical advantages on a lot of cars, allowing full lock to lock steering even when very low. 911s do have a shape of wing/arch that benefits from such a modification as well, but it got to be the case where people would narrow 'as much as possible' rather than 'as much as was neccessary', which created a whole new look of mega-tucked front wheels, which like it or not is very popular, and much more practical than having a car you cant steer......
it does have its practical advantages on a lot of cars, allowing full lock to lock steering even when very low. 911s do have a shape of wing/arch that benefits from such a modification as well, but it got to be the case where people would narrow 'as much as possible' rather than 'as much as was neccessary', which created a whole new look of mega-tucked front wheels, which like it or not is very popular, and much more practical than having a car you cant steer......