Something a little different in the post.

[p3asa]

..... No taping up panels gaps etc to improve aerodynamics.

No point in taping up the panel gaps as I'm sure they do the tests in a laboratory on a rolling road?!

http://www.transportenvironment.org/sites/te/files/publications/Real%20World%20Fuel%20Consumption%20v15_final.pdf

http://www.youtube.com/watch?v=LGQGzQY81Eg

[monkeyhanger]

..... No taping up panels gaps etc to improve aerodynamics.

No point in taping up the panel gaps as I'm sure they do the tests in a laboratory on a rolling road?!

http://www.transportenvironment.org/sites/te/files/publications/Real%20World%20Fuel%20Consumption%20v15_final.pdf

http://www.youtube.com/watch?v=LGQGzQY81Eg

If they manipulate the road load tests that are out on the open road then they can use less resistance on the lab tests (as the road load tests support the use of less resistance on the rolling road). All in your supplied link.  I don't believe that my GTD will ever be 20% more fuel efficient than my 170TDI Scirocco which had no eco tech on it. If that is the case then I would say VW have moved the goalposts to achieve these headline 20% gains in mpg and corresponding reductions in CO2.