I had factory 18s and thought that 19s would cause issues with the ride (due to the even lower profile tyres). i've actually found that ride has improved, however. Wider wheels and wider track will be the reason, i would suggest.
Also worth considering your suspension set up.
In terms of recommendations, try to stick to Audi OEM, in terms of fitment, build quality and looks. Lots of sellers across here and FB.