From F1's site:
One theory being talked about in India to potentially explain Red Bull's performance advantage related to the front section of the car's floor, commonly known as the 'tea tray'. A wooden plank runs the length of the floor and to regulate ride height the rules state that this may not wear away by more than 1mm over the course of a race. Unusually, recent thermal imaging footage of the RB9 showed the skid plates at the front of the tea tray getting very hot at low speeds. This led to suggestions that Red Bull might have found a way to attach the tea tray such that heat expansion in the materials used in its mountings raise the tray by 1 or 2mm at higher speeds, when increased downforce is naturally compressing the car closer to the ground. This would mean the team could run a lower front ride height at low speeds without wearing the plank excessively, and achieve a more constant gap between the tea tray and the ground through a wide range of speeds. FIA checks on the car found nothing illegal.
Well, Vettel did have a near 30 sec advantage over Rosberg. It's no Singapore, but that's still one hell of a gap. BTW if your interested, ScarbsF1 has more info and speculation on how the T-tray works.
On another note, I've realized the RB9 has probably been Red Bull's most well rounded chassis to date . The usual Newey trickery made the RB9 dominate the high speed/aero reliant corners, the KERS ECU traction monitoring system helped out when things got mechanical, and unlike other years there was no speed deficiency on the straights (really noticeable at Spa)