The a6 2.0 tdi has a 2000cc flat 4 cylinder diesel engine. The 2.0 means the 2000cc and the tdi stands for the diesel fuel.
About 20 years.
The red "I" or "DI" or even the red "TDI" stands for more power than the regular "TDI" (with no red letters). The more letters are red, the more power the engine has. Usually around 15 - 20 horsepower for each red letter.
The 2001 Audi A4 has 20 valves.
The 2005 Audi TT has 20 valves.
The 2003 Audi A4 has 20 valves.
The 2005 Audi A4 has 20 valves.
The 2004 Audi A4 has 20 valves.
The 2001 Audi TT has 20 valves.
The 2004 Audi TT has 20 valves.
The 2006 Audi TT has 20 valves.
The 2003 Audi TT has 20 valves.
The 2002 Audi A4 has 20 valves.