This week Fourtitude has published photo sets of several cars on location in northern Sweden for the winter driving event held by Audi AG. The new limited Audi A1 quattro and the vintage Audi S1 rally car grabbed a lot of the headlines from this event but another technical prototype in the mix also caught our eye. What outwardly looks like a current-generation A3 Sportback is actually running a new 1.4 TFSI that runs on synthetic methane gas. Audi plans to put it into production, but not until 2013 and after this current A3 has been replaced. Even still, this new photo set reveals some interesting details about the setup in preproduction prototype form.