My initial reaction when seeing the damage was that aerodynamically although the car was now asymmetric it wouldn't encumber his performance drastically. In fact my immediate reaction was I'm sure Adrian will be glad that damage is on the right side of the car with it being a clockwise circuit and most of the high speed corners turning left.
In terms of damage to their exhaust, the impact wielded quite a dent in one the exhausts primaries. Normally with damage of this magnitude I'd consider the impact on both engine power and longevity both of which I'm sure the team were concerned about. However in Sebastian's recovery from the incident I can find no reference to them dialing back the revs or changing the engine mapping. Sebastian continued to use full revs along the two long straights for his first stint pushing hard to recover the many places he had lost under the spin.
Red Bull opted to use a Resonator Chamber from Silverstone onwards (My original article looking into this: http://somersf1.blogspot.co.uk/2012/07/red-bull-exhaust-resonator-expansion.html) which will have undoubtedly helped to balance any inaccuracies formed by the new internal exhaust bulge.