your forgetting one key factor. The Driver.
Remember the Top gear article where clarkson tryed to repeat his lap on laguna seca for real, that he got on GT3 ?
he just couldnt do it, but the racing driver could. And clarkson was making a fast time, as good as most enthusiast racers do round there. But there is just something at the back of your mind that in most people takes over and prevents you from pushing the car too far.
in cars like the murcielago, its just that little bit more scary pushing your car to its limits round the B5576 or whatever than it is in something more mundane like a mini. Unless your a very talented driver, you just cant use that extra power that the lambo has on tight twisting B roads.