Aerodynamic efficiency: Narrow body, wheels outboard vs wider body enclosing

[aerohead]

Here's a link to a Wikipedia article and maybe the best photo of this solar racer.It was the fastest car in 1995 and the front wheel placement,wheel fairings as well as fuselage may be helpful when thinking of design.
File:TNE-II-Outback-1993.jpg - Wikipedia, the free encyclopedia
The front fairings might have affected the center of pressure,but the rear wheel fairing and upper fuselage probably added enough 'fin' area to create a rear CP/CG bias for good directional stability.
Goro Tamai,in his book,The Leading Edge,remarks that some of the solar racers' wheel fairing created sailing thrust in crosswinds.To compete in the World Solar Challenge,all cars would be required to demonstrate stability when encountering Australian land train bow and stern shockwaves.
I've only read through the book a single time and don't yet have any mastery of it's contents.I strongly recommend the book.Between it and Hucho,we get over 800-pages of excellent empirical streamlining science.