[aerohead]

1) 'The perfect aerodynamic shape is a teardrop.' Dr. Teddy Woll, Daimler-Benz, 2014.
2) the lowest drag teardrop has a fineness ratio of 2.5:1 and Cd 0.04.
3) the optimum shape for a subsonic, low drag vehicle, is a streamline half-body, based on the 2.5:1 streamline body of revolution, with Cd 0.08.
4) Adding wheels increases drag to Cd 0.13.
5) Wheel fairings can reduce wheel drag by 70%.
6) For an amateur, this would make a natural first approximation.
7) Dr. Wolf Heinrich Hucho recommended that car companies also use this as their beginning point for a Cd 0.09 automobile.
All present low-drag concept cars happen to fit the ASTs. Including Think Flight's boat-tailed 2022 Subaru Impreza Wagon, of est. Cd 0.1764 ( configuration #4).
--------------------------------------------------------------------------------------
The Aerodynamic Streamlining Templates are all based upon the 2.5:1 streamline body of revolution in ground reflection with the road surface.
--------------------------------------------------------------------------------------
I recommend that you study all of them and read every word.