I'm new here... having just bought my Audi recently... 2000 A6 2.7t. Sorry if this has been discussed before but I wasnt able to find any specific answer.

I've currently got 16" stock wheels and tires and I'm looking to go to 19". Basically I'm looking to find out how large of an aspect ratio I can go with before I start rubbing?? I'm also looking to get the smallest gap between tires and wheel well that I can, without cutting out the wheel well.

These are the specs I've got on tire sizes... if anyone has experience it would be greatly appreciated.
235/35/19 = 164.5mm + 482.6mm = 25.48"
245/35/19 = 171.5mm + 482.6mm = 25.75"
235/40/19 = 188mm + 482.6mm = 26.4"
245/40/19 = 196mm + 482.6mm = 26.72"
235/45/19 = 211.5mm + 482.6mm = 27.33"

In addition to what size I'm able to put on... how much of a gap will I be looking at between the tire and the wheel well? Will lowering springs still be an option? Or would I even want them?

Thanks in advance.