yea … S4 is pretty narrowed down for most of their things i’ve seen.not too much guessing when going OEM. aftermarket, well thats a different beast.
wheel spacer? thats the inner part of the rotor … and it fell out with the wheel. luckily (i guess) it happened to both sides in the front, so i dont have to toss 1 good. replace both and be done with them. and hopefully this was the cause of the ABS light i have on in the car!