This car is also awd irrc so wouldn't his tire sizes need to be the same..never wanted to stance a car so not sure how it work with tires. Honestly If I was you I would trade it for an a6 avant since the all road are mean to be semi off road
The 17x9 has about 1/2" more lip because imagine 1/2" on the outside and another 1/2 on the inside of the wheel.
That is why you'll see some 18x9's with -10 offset that has bigger lips than 18x12 +25 or so.
Just imagine standing behind your wheel, looking down at your drivers side wheel from birds eye view, the more the center more is <-- it has more offset, the more the center is ----> the less offset they have. That's why spacers will help decrease offset because it make the wheel further away from the hub.
Now here is some tricky one, some low offset wheel might have smaller outer lips, but they have a deep concave look by where the center meets.
Sorry, might be a little gibberish, that's the best i can explain it lol.
I do not want to trade the car in for an A6 advant, the allroad is the same exact vehicle it just has air ride suspension which is adjustible. The reason most ppl say just go get the A6 is cuz the allroad is limited to suspension upgrades unless I wana spend buttloads of money fobbing up top mounts of the a6 to inerchange with the allroad then just use the suspension. I've read diys on it dosnt seem to hard but I'd rather save my money lol.
But as for me understanding this I'm a lost cause, I need to study this so I can dumb it down for myself lol. But yeah ill try to contact the guys who built this allroad from stance nation and see what they ran into during the wheel fitment.