On video: the ultimate XKR

Jaguar is set to unveil the fastest XK ever at next month's Geneva show.

An optional performance pack raises the XKR's electronically limited top speed from 155mph to 174mph.

While the Speed Pack adds a revised front splitter, rear diffuser and a larger spoiler to improve stability at high speeds, Jaguar has also introduced an exclusive styling package which includes 20-inch black alloys and matching exterior detailing.