04/16/2017 All aluminum and poly hub centric rings didn’t fit perfectly, there were still vibrations at high speed, ordered another set from different vendor and this time it did fix the vibration.
I found a set of 2013 18″ Q5 wheels with 2k miles on them, like new for a great price. My A8L has 19″ as sport option with 255x40x19 tires on them, the wheels had curb rash and looked so bad, I had to change the tires, so I down graded to 18″ wheels 255x45x18 for softer and smoother ride, but I didn’t know about the hub center bored sizes difference between the Q5 66.6mm and A8L 57.1mm. The Wheel Works people told me about the hub center rings to get to eliminate the vibrations due to wrong size hub rings. The ride without hub centric rings is terrible, vibrations start at 40MPH. I ordered from a set from amazon for $9 and they worked very well.
Mount the wheel onto the hub, using hand and socket to tighten the lug bolt DIAGONALLY slowly to center the wheel perfectly because the hub centric ring may not fit 100%. By doing this, it helps to get the best center for the wheel possible.
With the hub centric rings, the wheels are no longer vibrate at high speed, but my wife still has the feelings that the wheels were not centered. Well, time will tell. The best is to get the wheels that actually made for A8L with 57.1mm center bored so we don’t have to mess around with the adapters because none of them will fit perfectly as the original wheels themselves.