Aero Rear wiper for an S3... That fits!!
I thought I would just mention this incase it has not been done yet.
I bought some aero front wipers for my S3 from VAG-parts and was informed that they did not have a rear aero wiper kit for the S3, only the A3. I was told this was due to the spoiler on the S3, causing the A3 wiper to hit it. The guy at VAG-parts said that some people end up cutting the A3 wiper to help it fit.
Luckily, on a french S3 website, they listed part numbers for a setup that will fit the S3, and yes it fits, however just to make you aware, it is a little shorter than the stock wiper, about 1cm, if that.
6Q6 955 425A is the wiper
6Q6 955 435B is the cap to cover the nut
6Q6 955 707A is the wiper arm.
Hope this helps. I will try to post some pics in the gallery.