I also test drove 2 Audi S3's. One was a demonstrator, brand new, and one was a used pre facelift model. The new one was ok, but lacking something, and I didnt like the steering at all. It was quicker than my GTI but a lot more expensive and missing a "wow factor". It was also manual and it felt a bit like it had clutch grab especially from 1st to 2nd and that made it "clunky" for me to drive.
The used one, pre-facelift, actually drove a lot better and I liked it a lot more, cant really explain why but it just felt better. It changed gear smoother and seemed to pull from lower down the rev range compared to the other one.
I test drove a lot of cars at the time, and was about to give up and stick with the GTI for another year, until I test drove the 135i Coupe...The rest is history as they say!
I have nothing bad to say about Audi as I have owned 6 of them from new, but the S3, IMO is missing something from its driving experiance. Maybe a lot more fun remapped, but if you want some real fun, its not the one I'd choose.