This is the first car I've owned with 30 series tires (prior to this it was 35 series tires). It stands to reason that a smaller sidewall tire will transmit more NVH to the cabin compared to a larger sidewall tire and I believe that is what I'm noticing. By no means is it horrible and most obviously don't notice or mind it.
If/When I swap out wheels and tires for cold weather driving, I'll select a smaller diameter wheel-tire combo. This shed some light on my belief about the tires.
The RS5 is an epically good machine. After spending time behind the wheel, you begin to critically identify areas to improve. :)