The required gas is premium, it says so right on the gas cap and the manual, however, the previous owner of my 2000 A6 2.8 used regular gas for the entire time he owned the car, it doesn't effect the performance for normal driving unless you plan on racing you can use whatever gas you can afford :)
The 2004 Audi A6 is a gas-powered vehicle.
The 2009 Audi A6 is a gas-powered vehicle.
The 2001 Audi A6 is a gas-powered vehicle.
The 2003 Audi A6 is a gas-powered vehicle.
The 2005 Audi A6 is a gas-powered vehicle.
The 2011 Audi A6 is a gas-powered vehicle.
The 2013 Audi A6 is a gas-powered vehicle.
The 2007 Audi A6 is a gas-powered vehicle.
The 2012 Audi A6 is a gas-powered vehicle.
The 2002 Audi A6 is a gas-powered vehicle.
The 2008 Audi A6 is a gas-powered vehicle.
The 2006 Audi A6 is a gas-powered vehicle.