Took our 2011 TDI wagon out to our local club's ice cross today. Lets just say that I was only 50 seconds off the FTD (combined best morning and afternoon runs, I came in just under 300 seconds total), but then they had AWD and studs where I was playing with a FWD with just normal blizzaks.
No issues getting the car to rotate with a GTI rear bar installed, just lift and turn in a little farther than you expect and the back end would do its thing. Unwind the steering wheel just a little and the back end would immediately come back into line, very well balanced.
Lots of trouble getting traction for any of the tighter corners bigger than 90 degrees (i.e. my brain said I should be able to go faster, but the ice definitely had other ideas), and I'm sure that the stability control was interfering with the throttle lots on the bigger corners (usually right near the end of the corner). I'm going to try to disable it for next weekend and see if its any better - I did press and hold the traction button, but I think that the stability system will still override throttle if you are out of control for too long.
I was definitely worried as I drove across the lake to the corner where we were setting up - there was drifting snow, and while not deep, it had a crust and was like sugar underneath, so if I slowed down at all, traction disappeared quite quickly. The organizers ran the AWD/RWD studded groups first, so by the time I ran the course was quite well cleared.
John