They're hard to compare because their revisions aren't year for year comparable. No doubt, when the GTR first came out it caught Porsche napping and destroyed the Gen 1 997 (as featured in the vid) when it came to performance, but then came the Gen 2 997 with PDK...i'd call it even, and of course there is the Turbo S.
Not read/seen/heard much about the 2012 GTR but i appreciate that it has moved on the game once again. However, i doubt Porsche will let themselves get mugged off so easily once they bolt a turbo onto the new 911...
Worth pointing out that the second time round the GTR didn't pull away that much, and that was with a slipstream. Clearly on that first drag the 911 driver lifted off.