Ironically it's not, it's a sodding Enzo underneath!
No it isnt, its somewhere between 300 and 400% stiffer in the chassis for a start. A man at Dallara told me that, he also told me that the stiffest chassis in production was the RR Phantom, by quite a long way.
Same (albeit modified) chassis, same engine, same gearbox... If it looks like a duck etc
Interesting about the Phantom, I'd never have put that up there in the stiffest chassis list.