Aluminium construction came from A8.
Agreed it is important in Audi's history (Note, History)
The E models are further development of PD diesel engines which the A2 just happened to have, however the later common rail engines are far superior and you will see the PD vanish very soon. The Blue motion project has nothing at all to do with A2.
I have formed my opinion on running several A2 TDi diesels from the very first cars that landed here and knowing all the failings, problems and the things it was good at.
As for fuel efficiency I found it was no better really than, for example, an A6 1.9 PD I was also running you just had to stop more times in a A2 because the fuel tank was too small to give it it's small mass.
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