[Phase]

Originally Posted by aerohead

Any dust transported within the wake, which presently does not accumulate, would be forced to adhere to the 'jelly,' perhaps revealing features of the base area that would otherwise remain 'invisible.'
Allowing 'scrubbing' air access to the taillight lenses might be an advantage, safety-wise, as traffic behind you would 'know' what you're 'doing.'
Mercedes used to incorporate horizontal ridges into their plastic lenses, so that any back-soiling would be limited to only half the surface.
If you were going to add fairings behind the wheels, you'd want to add them in front as well, just as with VW's XL1, MG EX-181, etc..
Wheel fairings are capable of reducing wheel drag by 70%.

When you say flaring are you talking about on the side of the bottom around the wheel skirts or are we talking about boat tailing under And in front and behind the tires?