I think the Bugatti just wouldn't handle well enough on a race track to compete. (lets say nurburgring)
Even though I love the Koenigsegg I don't think it would win, it's becoming outdated, though is definitely a great all-rounder in the group and could win.
The Porsche would probably out-handle the others being one of the lightest and it's 4 wheel steering and advanced electrics. (probably the most advanced)
But it lacks the horsepower of the other cars. >600hp
The Lambo would definitely be fast in the fast sweepers (due to downforce) but I think it would lose due to lower horsepower. around 750hp
The Pagani same horsepower problems and not as much areo to help it.
I think the Hennessey Venom has a good chance to beat at least the bugatti. But I haven't heard anything about it's handling. soo I don't think It would win. It would probably win in a 1/2 mile drag race though.
I think the race would come down to the Ferrari and the Mclaren. The both come to around 900hp,(middle ground) got enhanced handling and responsiveness from their electrics, and have always made fast cars. Ferrari should have better Aerodynamics and a few other things than the P1 though. So I think the Ferrari would win granted the extra power of the Hennessy or the Koenigsegg doesn't beat them out. (yeah I don't think the bugatti has a chance, sorry)
1.Ferrari
2.Mclaren
3.Koenigsegg
4.Hennessey
5.Lamborgini
6.Porsche (isn't it faster on the nordschleife than the Veyron?)
7.Bugatti
Secret entry:Audi R20