This is very sad - not many RS4 Avants in this world and now apparently one less. Driver is fine - demonstrates how tough these cars are.
Added bit of chilling for me - looks like my car (see sig - A4 not RS4).
Video from UK track day at Castle Coombe. If you search on YouTube using "track day crash Castle Coombe" you'll find that corner is a popular (unpopular?) place to demonstrate what happens when the weight goes forward while the back end is out.
Amazingly - I think this is a video of the same guy on the same day doing a powerslide/spin/no crash in the same corner -
http://www.youtube.com/watch?v=DkkDCM_ybaU&feature=related
Do they simply have no rules or marshalling at UK track days?