Are you sure about this?Auto mode is a big negative. S6 does wear the clutch faster than the S4.
I drive my car 75% of the time in D2 also. Absolutely flawless.Well..... with a 102,000 miles on mine, clutch replaced at 92k I can say around 70% of my driving was done in D2, the other 30% would have been nasty viscous driving, DSC off, P500s, S6,
I've heard almost every person say that the car is not driveable in D2 mode, I'm not sure if I have some sort of different or lucky transmission but it's totally fine for me, albeit most of my driving is motorway driving.