You might have better luck in the Audi forums. I've seen a few b5 s4's rolling round on ultraleggeras.
I'm looking to test fit 17" and 18" OZ Ultraleggera on my MkV R32 (specifically over my Stoptech brake kit).
I am located in Boulder (I have three floor jacks, tons of tools and jack stands, etc.). I can come to you or vice / versa.
Thanks, I appreciate your consideration.