It's unfortunate I can't reply to the reviews, but I'll try it here... I can be long winded this way so maybe it's for the best.
On the Hobbs lap @ Silverstone: as Mantas said, it was 19C on a drying track with a damp patch in one corner. I'd call that "green" for sure, after factoring in the lower general grip of the v10 tires I'd try it at maybe 95-96%.
And when you achieve it, remember that the real car was doing development testing that day and still had some bugs. The front brake hydraulic assist was lunched and so the brakes were only being about half used... full braking force required something like 200kg pedal pressure which obviously didn't happen with human beings driving. That impacted stopping power and generated a lot of heat, which impacted stopping power. That has not been modeled in AC.
Also the rear suspension, in typical Jaguar fashion at the time, used the driveshafts as load-bearing links, essentially as part of the upper "wishbone." This had not yet been perfected for the loads and speeds of the XJ13 and the shaft ends were floating in the gearbox, causing uncontrolled camber changes on the rear wheels under cornering loads. Obviously we have not modeled that in AC either. (It was eventually sorted after a few rounds of testing, so even if I could, I wouldn't.)
And we're definitely using better, wider tires than were on the car that day in 1967. They're more or less a detuned version of the KS GT40 tires, as the Dunlops Jaguar was using were not quite on par with the Firestones and Goodyears for road racing. But they are the larger, later size as used on the XJ13 after its rebuild in the early '70s, part of which included flared fenders necessary to fit wider rubber. (And to add to the suck salad of the tires, the ones used in that test were found to have been the incorrect compound, with less grip than the ones specified - and only on the rear axle IIRC. David Hobbs is truly an alien, and his career would go on to bear that out I think.)
Anyway, the testing recap from Silverstone suggests that low 1:30s were possible once all the bugs were ironed out, and while I think that may have been a bit optimistic I certainly think 1:32-1:33 was in play given the same testing conditions. (For context, the small block GT40 was 1:35 flat and the fastest car in the world at the time, the Lola T70, did it in 1:28.8. Test conditions unknown on both times.)
