I believe they will, even though the offset is ET43 people have been going lower that that I believe. I have a 2008 8P S3 with KW variant 2 coil-overs, not sure how relevant this is. The wheels are off an A4 and they are genuine.
I bought them already, seller is about to book courier, just double checking!
Thanks! Here is the link:
Audi original 18" RS4 alloys | eBay