Actually, now that I thought about it a little bit, the thing with the P1 is that they didn't go far enough, and give it an electric turbo, like the F1 units and the Le Mans prototypes have.
That would have been a proper technological game changer, but like this it just looks like a -properly fast- race car for the street, with a little bit of electrical help, where the 918 is just a more relevant package. Of course, these cars are also two slightly different exercises in marketing, with McLaren selling race cars for the road, and Porsche offering machines that are to be understood primarily as vehicles, but with little to no compromise, when it comes to having a car that is responsive and entertaining.
I would expect a P1 to be slightly faster around a dry track, with a competent driver behind the wheel. In any other condition the 918 is probably much more manageable.
Also WTF was that spinning out bit in the BMW all about? Clarkson drove a P1 at a wet Spa, and gets taken out by a spot of aquaplaning on his "home track"?
...also I feel the GTI was a bit miscast - there should have been an S3 or Golf R in its place, especially when starting the entire piece with the AMG45.
Overall this episode wasn't too bad though. The bit on the 918 felt a bit rushed, but then I suppose the manufacturers were probably quite heavy handed in what people were allowed to do with those cars.
It was a bit funny to see the 918 at Dubai, just after Chris Harris had the P1 there as well... Apparently the track has some good connections to the industry