It finally arrived! Today is a joyous day as it signals a new era for the S6. Standalone engine management is always a very big upgrade for a car as it opens up a lot of possibilities for tuning and setups.
I ended up going with VEMs because of its long history with Audi C4 support and the ubiquitous nature of this solution in the Audi community. It is tried and true and although it does tend to have some issues with knock sensors and interference on occasion, I trust that it will work for my solution just fine. I purchased the ECU from Marc @ EFI Express as usual. It arrived with several harnesses to convert a few pins because I wanted to keep everything easily reversible rather than de-pinning and re-pinning the stock harness. Marc has been a great ally to the community so I try to support him whenever I can.
The kit also came with a few spares and such in case I wanted to do something else or a connector breaks, etc. I also have the bluetooth adapter