There have been several keys to Audi's success in LMP1 over the past eight years. Sheer speed hasn't hurt, but there were times when other cars were as fast as the Germans. Efficiency and fuel economy have been among the biggest boons to the R8 and now the R10. Being able toe swap out the entire rear suspension and gearbox module in a matter of minutes was a huge boost to Audi at LeMans. The direct injection that Audi used on the gasoline powered R8 helped them get more power from the same amount of fuel and run farther. And the introduction of the diesel R10 last year allowed them to run an extra 3 laps per tank at the the 8 mile long LeMans track.
Now with essentially no competition in their class in the ALMS, it appears that they may be considering dropping out of that series. It would be nice if Peugeot would bring their new 908 HDi LeMans challenger over to take on the R10 in the American series. More likely, the series will go into another period of renewal, with a new set of rules being developed to attract new competitors. Hopefully the next generation rules will encourage more use of alternative fuels and provide more incentive for improved fuel efficiency.