The facelifted S3 you are looking at and the RS3 both use the same Gen IV Haldex AWD system.
Prior to the facelift, the S3 used a Gen II Haldex system which didn't pre-charge so there was always latency in the rear wheels kicking in.
With the Gen IV 100% of torque can be directed to the rear wheels if required.
"Proper" AWD as the purists would call it would be via a Torsen differential. Not electronic, but entirely mechanical eg Torque-Sensing. This system is used on all Audi Longtidudinal applications. Its not available in transverse applications such as the 8P platform.
As for the car.. Its certainly capable, but looks dated now. Sat nav will be a generation behind what you are probably familiar with.
The K04 turbo'd 2 liter though is virtually bombproof so you could easily see 315bhp from a stage 1 remap.