At first I thought that it is a rendering of some sort, then I thought it is a concept to preview their upcoming central seat car, but then I realized it is a special edition that is based on the 720S.
This reminds me of Ferrari's special editions that are based on their road cars such as the models that were based on the 458 Italia.
Anyway, there is an interesting discussion regarding this Senna version to be quicker than a GT3 car...
(LONG POST BELOW - COULD BE BORING!! YOU'VE BEEN WARNED

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I'm a big fan of GT3 racing and follow a number of their championships (Blancpain GT, ADAC GT Masters, GT Open). To give an idea of the difference between the performance of a GT3 racing car and a road going supercar / hypercar, taking a look at tracks that provide a timed lap for both the race cars and the road going cars might help. Here is a list of some tracks (the times of the race cars are qualifying laps):
Sachsenring (3.645 km):
Road car: 1:26.77 / Porsche 918 Spyder / Auto Bild
Race car: 1:17.33 / Mercedes-AMG GT3 / ADAC GT Masters 2017 season
Hockenheimring GP (4.574 km):
Road car: 1:48.00 / Radical RXC Turbo / (
Hockenheim GP lap times - FastestLaps.com)
Race car: 1:37.51 / BMW M6 GT3 / ADAC GT Masters 2017 season
Spa Francorchamps (7.001 km):
Road car: 2:32.14 / Koenigsegg One:1 / (
Spa Francorchamps lap times - FastestLaps.com)
Race car: 2:16.82 / Lexus RC-F GT3 / GT Open series 2017 season
Circuit of the Americas (5.513 km):
Road car: 2:17.5 / McLaren P1 / Jason Hart
Race car: 2:04.26 / Lamborghini Huracan GT3 / Pirelli World Challenge 2017 season
Bear in mind that performance of a GT3 race car (or race cars in general) depend on the setup, so there is a difference in performance on similar race tracks between different championships, due to a different Balance of Performance (BoP), and a different rubber compound (though I'm not sure if this is true, so correct me if I'm wrong).
A GT3 race car usually weighs between 1200~1320 kg / 2710~2865 lb, with a range in engine output between 500~550+ HP. Combining this with the high level of downforce (I'm not sure of the exact number, but I think it's about or above 680 kg / 1500 lb at around 200 KPH /125 MPH) a high drag ratio, and the gearing ratios, the GT3 racer can reach a top speed between 270~278 KPH / 138~173 MPH, and their acceleration is believed to be around 3~3.5 sec in 0-60 MPH.
These cars gain their time in the corners due to the mechanical grip from the racing slicks and the aero grip from a splitter, dive planes, flat floor, diffuser, and a wing.
Saying that this P15 Senna will be faster than a GT3 race car is impressive if true, but I think it'll be difficult to shed more than 11 seconds on the Sachsenring for example (11 seconds to beat the 918 as a road car and to be faster than a GT3 racer), unless racing slicks will be used. There are some advantages that the McLaren enjoys, such as a superior power to weight ratio (668 HP/ton for the P15 against 416 HP/ton (on avg.) for a GT3 racer), a higher top speed, and an active aero mechanism, so I could be wrong.
Thus is indeed a big Statement! The remaining/interesting question would be: both on their "natural" tires (Trofeo R vs slicks)?
This I cant imagine. In this case the McL Senna would do a Nürburgring Nordschleife laptime (sport auto setup) of around 6:15 then!!! Current top GT3 cars in VLN are tracking the whole track including the GP course section in about 7:55, while GP section takes them about 1:40.
Thirty seconds faster than the current record holder 911 GT2RS??? I can't imagine this. This is almost Stefan Bellofs all-time-record!
A comparison to a GT3 car (if it happens) on the Nurburgring Nordschleife is not completely logical in my opinion, since some portions of the track favor high power and brutal acceleration, such as the Döttinger Höhe which is the longest straight. As a result, some of what a GT3 gains in the corner will be lost on the straights (The 991.2 GT2 RS reaches a top speed of around 305 KPH on the Döttinger compared to 270 KPH for a GT3 racer).