And what happends when you get M135i xDrive, and there is one...

I think that these two cars are uncomparable, current S3 is proper rival for curent M135i/M135i xDrive, but I'm afraid that in that case also, result could be even more in favour of BMW.

At the end, we have to addmit that BMW and Audi provide simmilar numbers, but very different cars, its all down to that what customer/buyer/driver wants from its car...

P.S.

I never saw Chriss Harris as a "Audi hater", his Audis reviews are OK, if I remember correct, his review of B8 RS 4 Avant is very afirmative.
The guy just loves rear wheel drive cars, and thats it...

Hope I didn't ofended you TP, RS 3 is brutal car, just different from BMW.