with the Apex's at the rear and front of the car,, I then just started squaring off the bottom and added points where needed,, After I got my final shape, I cut the wheel opeings out. added a little trim to them. then did the same to the res of the car. Just went around and seperated pannels with 2 offset curves to get the pannel gap's.
Pretty quick model. I made it in about 3 hours total,, and about 1 hour to get the main shape out of the Sphere.
I'm gonna add a spoiler that will follow the long lip on the rear. it might make it look a bit bigger in the rear.
Modeled in RHINO3D and Rendered in MAX4