Everyone is talking about 60' times and ET being off. But the thing that would be bothering me is the trap speed. Trap speed does not vary much with the launch, and is a good indicator of the HP being put down. A bone stock 550 should be 108 mph. He is only picking up 2mph or so with 100 more horsepower. 500 hp in that car should be running more like 113 unless it is really hot out and/or high elevation.
It seems to me that the 500 HP M5 (the outgoing model) has run as high as 118 trap speed if memory serves, and 115 plus easily. I realize that car was a little lighter, thats why I'm giving this the benefit of the doubt and saying he should be 113. Maybe even a bit higher.
2012 BMW 550 M-Sport
2015 Audi A7 Prestige
2014 Lexus GS350---Wife's car
2013 BMW 1600 GT---2011 Kawasaki Ninja 1000---2012 Ducati Panigale