You could always find a C6 A6 4.2 Sport...mmmm
No 6mt available in the C6 A6 lineup though.
I'll +1 for the Allroad. Part of me always wanted to build a Stage3 Allroad to fuck with people.
With proper maintenance the 2.7 is a reliable motor. They just suffer from DSM Syndrome.
They are cheap enough that kids buy them with 100K+, and immediately try to figure out a way to up the power without addressing all the rest of the issues. My B5 has approaching 160K on it with over double the factory HP I have no concerns winding it out in 90+ degree weather.