Hi,
I'm a little more "comfortable" with this version, which has a slightly flatter underside than the previous version:
The symmetry may work in free air (on the airplane), but on a car on the ground, I think that the underside needs to be less sloped. It is also slightly longer (nearly 1/2 the length of the car) and the rear fascia is now 12" high vs the 10" of boattail #4.