I drove the GTI around the Corporate Hill Short Course and rode in the R around the full Eastern Creek course today. Both were fantastic fun, and the GTI's brakes held up despite copping a lot of abuse on the short course.
The hot lap with Steve Owen was brilliant, he didn't hold back. As a passenger you can feel the rear doing more work on the track to launch the car out of corners, however its ability is far beyond my talent. That said the pace he was carrying into the turns that are also part of the Corporate Hill course felt very similar to the GTI, its just that he was braking later (his ability let him) and getting on the power sooner (his ability plus the AWD at work).
The R only had 700kms on it, so much for the careful run in period. ;)