I love the majority of the overall shape and design.
However, I would not use it because I think the ends are out of place. When it comes to rear spoilers, I prefer them to blend in and have "just enough" in terms of noticeable features.
I drew some lines that may help you understand what I am saying. I think making the sides come down "sharper" and thinner...and matching the line on the car, would make it a homerun. I am not the majority, but I bet more people would prefer it.