I have a 2013 A6. Was wondering whether anyone that has had the APR tune done to their car with the smaller pulley, has any comment as to reliability, performance, drivability, etc.

 

I have a 2013 A3. I put on a cat-back exhaust and performance air filter. This qualified it for an APR Stage 1 tune,and the results are great. I can switch between stock and APR tunes,and the extra power is very noticeable with no downsides.