Deco Rides has been around since Scrape, the Zephyr clone. They are every bit as aerodynamic as their inspirations from the 30s. But the world has moved on from the small interiors and fussy details.
Their wheel pants are a nice ('spensive) part. The closed top cars will have better aero. Compare the new Morgan Aero8:
http://www.muchocars.com/the-new-morgan-aero-coupe-2012.html