Okay, bit of an update here.
I've been poking my head under VW's skirt and found out a few juicy details.....
MKVI GTI engine with a larger turbo. I don't know which turbo, but my suspicions would lay squarely at a revised K04.
This would mean that you'd be able to get 380bhp and low 12 second 1/4 miles out of it at stage 2+
I've also been told to hang on for a few weeks as there will be an announcement about the ED35 pretty soon