Ignoring the 911 times which were all essentially performed on a different track layout with exuberant grass usage, look at the 650S, Speciale and Huracan warm braking test from 100-0kph. The Speciale is generating almost 10% more deceleration force at 15degC relative to the 650S at 25degC. Now all these cars have more than enough brake to lock the wheels at 100kph, so the limiting factor is the level of adhesion between the tyre and the road, pointing to the fact that the 650S is on inferior tyres, yet still running within 0.39s of the Speciale due to massive straight line speed. Even the GT3 being tested at 7degC in the middle of winter is generating more braking g in the same test on the MPSC2s.
So in summary, looking at this test another way, fit Trofeo Rs or MPSC2s on the 650S and it'll be in the high 1:31s.
It's a great source of confusion that the PZero Corsa System is consistently referred to as 'PZero Corsa'. Two different tyres. The PZero Corsa was a legacy semi-slick competition tyre that was replaced by the Trofeo R. Note tread difference.
PZero Corsa
http://www.tyrereviews.co.uk/Tyre/Pirelli/P-Zero-Corsa--.htm
PZero Corsa System
http://www.tyrereviews.co.uk/Tyre/Pirelli/PZero-Corsa-System.htm
The confusion is further compounded by the fact that manufacturers are allowed to underrate treadwear and frequently do because it makes the tyre look sportier, hence why the PZero Corsa System ended up with the same UTQG treadwear rating as the Trofeo R, even though anyone will testify that the actual treadwear is nowhere remotely close.
So what we consistently end up with is a McLaren on a max performance summer tyre against other cars wearing competition semi-slicks and soft compound competition Dunlops and journalists complaining about cornering performance. Meanwhile in the aftermarket, people fit MPSC2s on the 650S and all of a sudden the cornering performance starts to equal competitors and the straight-line speed remains.
As a side note the Huracan lap didn't look like a very decent effort on behalf of the tester either. It wasn't using the full track width and I was extremely impressed by its handling and traction. I didn't see any of the alleged 'understeer' referenced in the video.