This setup is .22% different in diameter than factory 20" wheels. This will work all day for those with factory 20's. I recommend a site called willtheyfit.com. Enter your current size and the size you are wanting to switch to. If they are within 1% overall diameter you're good. Make sure the two new sizes are within 1% as well. With AWD you want to stay within 1% diameter to not stress the AWD system. I have a set of wheels and tires on order this size and they will work for 2018 RS's with factory 20's. I haven't run any numbers 0n the 2017's with 19" wheels though.Is this setup safe to run? A lot of people tell me that the rolling diameter of the front and rear do not match and that it would ruin the awd system? Does it rub? I am thinking of this setup but afraid it would run.