Turns out I don't have one single good pic of my decklid but mine has spoiler delete option. This may give you a slight idea:
![](http://i699.photobucket.com/albums/vv356/voxguy/2011%20Mustang/e3e7b704-bf3e-471f-89d9-a2d99418a3e6_zpsfa66a1fe.jpg)
I agree it needs something but I don't like any of the ones available. Plus I had kits on my Fox bodies and always wished I'd not done that. Tougher to remove than never install.
The best looking IMO was the 2011 Saleen decklid. Just had a tiny lip that went more out than up and balanced out that sorta weird rake the back half has. Only problem is it's super expensive and I don't think you can do it without the lower valence which I don't like all that well.