Being no vendor has come out with a tuning tool that allows to tune the A6's internal controller (TCM) if you add engine mods that also effect the A6 you have no way to make tuning adjustments and the mods increased HP and torque could have a bad effect to the A6 until it was tuned to handle the powertrain's effect from HP and Tq increases.

The engine can be tuned so for now I suggest the tune and a good aircleaner that allows only outside air being taken into the engine's intake.

Tune and CAI will get you good HP gains without need for TCM to be tuned