Yes, Aerohead mentioned that narrowing the rear track can have as much as a 40% reduction in drag.
I think the Eolab is subtly narrower in the back. They pushed the rear wheels back somewhat so it affected the rear seat width less or not at all.
2014 Renault Eolab Concept Boldride.com - Pictures, Wallpapers
The Eolab is a 4 door
including the hatch.