Audi's biggest and most expensive sedan has been on the market for too long. Sure, it still looks as good, or better, than its competition, but it's a little behind in the technology and power department.

This image of the 2011 Audi A8 was caught testing at the Nurburgring recently. It's scheduled for a official debut in the next few months, but this test mule gives a pretty good intent of what it will look like.

Power will continue to come from a V8 in standard models and a W12 on the top-of-the-line version. An aluminum spaceframe chassis will form the structure and quattro all-wheel drive will remain standard as well.

Look for the official debut of the 2011 Audi A8 at the 2010 Detroit Auto Show in January.