Hi Karol3dd,
Not sure you've already made your decision or not - but I just purchased a 2019 a4 b9 with 19" wheels (fitted originally since it's an S-Line) and I am thinking about replacing them to 18". IMO the ride is kinda too rough and I also am not a big fan of such low profile. It's 245/35, which is in my opinion way too low.
Cheers,