Well, Veyron has awd, and a significantly larger footprint, proportionate to its power advantage over the SLR, so it will get better traction. There is no way the SLR would prevail here, its battle is lost before it starts, or very shortly after... hehe. I do notice though that the corners are taken a bit easier by the SLR, with slightly less weight. But then again, the SLR driver is not worried of piling a 1.35 million dollar machine against the rails.
For the record, the Enzo, Carrera GT, Zonda, and Murcielago would appear equally slow in the company of Veyron.