In a nutshell, Mirage77, the S3 will be more focused and far more sporty. The current 3.2 quattro is, well, a little soft in my opinion. And it's every bit a front-wheel drive biased Haldex setup with 100% of the drive going to the front in normal conditions. In the S3 more of the torque is sent aft as a predefined torque-split configuration under neutral driving conditions.