It's hardly a race that is it? One guy leaning out of a car filming - imagine the aerodynamic drag that was causing. Also, was the guy in the S3 really pushing it? You just don't know.
Which car is faster could only be proven at a track, Santa Pod for example. Even then its dependant on the driver, reaction time, weight, gear changes etc.
However, they are very close in terms of performance, just looking at the numbers...
8P A3 2.0TFSI...200PS....280Nm
8L S3 1.8T........225PS....280Nm
So how anyone can say "I'm surprised it didn't pass the S3" is beyond me, unless the 8P A3 was remapped. It would be all down to the drivers to make one car pass the other.
A real world experience for me was on the start of the toll road once, heading north, with a new Golf Gti 2.0TFSI behind me. There was nothing in it to be honest. I did start to pull slowly away from about 120 but, you could argue the guy may have been easing off. You could also argue that the guy may only have kept with me because he was in the slipstream created by my car in front. I did move over, but he didn't pass.
Its swings and roundabouts. With cars with such similar performance figures and weights, its all down to the drivers.
In my opinion of course.
AL