Looks great, I love it. Did you think about feathering the spoiler right to the edge of the trunk lid (side to side)? I think that would give it a nice flowing look. Maybe even an oval LED flush 3rd brake light built into the spoiler.
I mocked up a template that feathered to the edges but then I tried this design it gave it a more custom pro mod look. Considered the third brake light and it's still a possibility to add also consideded a back up camera eye. Like I said it's not done so something else could get added....but not subtracted.