Last month, Top Gear magazine put together a truly unprecedented selection of supercars on one of the worlds best driving roads: Italys Stelvio Pass. The fastest production ever, the Bugatti Veyron Supersport, in its first-ever performance car showdown. Ferraris new FF. The McLaren MP4-12C. Porsches finest ever 911: the GT3 RS 4.0. Jaguars new XKR-