A friend is interested in buying a 2009-2010 Audi A6 3.0T, but asked me to look into any problems the models has. So help me out here by letting me know if you have any experience with these cars. For those who don't, feel free to mention any information on problems that these models are apt to have. If this guy buys the car I get to drive it, so for god's sake help me people!

Edit: I'm seeing issues with the water pump and xenon headlamps, anything else?