[Christ]

My comment at the beginning of this still goes unanswered, that it must have some interaction with flow when you consider the tapered/rounded sides of the car, and the obvious wrap-around effect that the flow would have there, coupled with the wrap of the spoiler around and over the tail light section, obviously protruding into the area above the sides of the rear wheel housings.

I can't say authoritatively whether it will adversely affect flow or positively affect it, but I'm sure it's not benign.