Hi,
I found some more details on the VW 1L over at TreeHugger.com:
Most Fuel Efficient Diesel-Hybrid in the World: VW Shows New Version of 1-Liter Concept Car (170 MPG) : TreeHugger
The Cd is 0.195 (vs 0.16 for the previous generation), and the weight is 380kg (vs 300kg of the previous generation). The drivetrain is 122kg (must include the batteries and the diesel and the electric motors). The batteries and the electric motor are in the front, so the electric drives the front wheels and this also lets it do regenerative braking.
There are new pictures, too: