Short answer - it is un upgrade.
The chassis tune is better and it feels better. The extra weight over GTI (150kg) is not a problem really. 18" vs 19" tyres make a huge difference for steering feel though.
And it is absolutely true it feels so much more stable than GTI above 120
4WD is more of a safety option on the road. On the track day it behaves the same way as FWD but it makes the corner exit phase easier. It's not great fun as but I'm of the opinion only RWD really is.
I wouldn't go back to GTI.
As for the price - well, UK is not the main market. Germany is and the demand is high there so the price is aimed at that market. UK price will be just a simple exchange rate conversion plus some local taxes.
Mk7 GTI will not be here until 2014. S3 will be earlier so we should be able to see what's on the offer. New A3 (build using the new modular technology) is getting good reviews. True LSD will be worth more than 30bhp. I'm sure it will be more than £30k.