Not sure if it can be done on the '08 models (check Chef's noob guides which is perma-linked on top of the messages here) as this was figured out in the '06 models. I know after coming from a BMW 3-series to the A3, that the steering was quite sensitive compared to the stiff steering on the Bimmer. I've since gotten used to it and actually become comfortable with it (takes a few thousand miles but I'm adaptable!). As for the drifting off, definitely check the alignment. Mine barely drifts, specially going on highway straightaways. There'll always be slight corrections that need to be made but no road is ever straight enough for me to test out where it's properly aligned or not. I gotta take the techs at their word for it!
Welcome to the A3 club though!