Car and Driver tested the 2012 GTR and got an 11.2@126 out of it in the 1/4 mile. No F13 M6 has come remotely close to this trap speed. However, the all wheel drive launch of the GTR helps big time in a 1/4 mile sprint. Also, MotorTrend's numbers for the 2012 GTR differed considerably with an firstname.lastname@example.org which seems more much inline with the 2012 GTR's dyno numbers. Was the Car and driver car a ringer? Nissan has supplied ringers before and the 122 trap sure seems much more realistic. Owners have hit 124 mile per hour trap speeds themselves with stock 2012's so the truth is likely somewhere in the middle:
The convertible F12 M6 has been tested in the 1/4 mile by Insideline and they hit a 118 mile per hour trap speed in the much heavier cab which weighs in at 4,398 pounds. So is the coupe which weighs roughly 300 pounds less capable of 122-123 mile per hour trap speeds? Yes, certainly with proper rubber.
Check out Insideline's 2012 GTR dyno numbers:
Now take a look at the F13 M6 dyno numbers:
Based on power on paper a top end roll should favor the M6. The weight disparity between the two cars is not all that large and all wheel drive does offer greater drive train losses so a roll on will favor the rear wheel drive setup. Both cars have dual clutch transmissions. Gearing on the top end seems to favor the M6 as well.
Can an F13 M6 beat a 2012 GTR from a roll? It's feasible, but it certainly would be close with a longer race necessary to favor the M6. It would not be the epic beatdown we see in the video below. The GTR owner states there was more than one run yet they were not put up. That leads BimmerBoost to believe the other runs certainly do not look like this one.
This certainly is controversial and BimmerBoost's money is on a "real" race between the two cars in stock form actually being close assuming no driver error which is likely what happened to the GTR here. Either the wrong gear or wrong mode but either way this is a misleading result based on the available data for both cars: