Jaguar XFR and XKR: 2009 Detroit Auto Show

Doing the Queen proud out in Detroit, Jaguar has unveiled a new XKR and a performance version of its saloon, the XFR. And both are powered by a most excellent-sounding supercharged five-liter V8.

It isn't an expanded version of the existing 4.8-liter V8, but an all-new unit developed entirely in-house by Jaguar. Featuring direct injection and clever new variable cam timing, it puts out 510 hp and will propel the XKR to 60 mph in just 4.6 seconds, with the XFR just 0.1 seconds slower.

Impressive stuff, and – better still – the V8 is clean... by V8 standards, at least. Though we're yet to get the exact figures, it puts out under 30 g/km of CO2, whereas the V8s in the BMW M5 and M6, and Merc's E63 and SL63, all produce about 50 g/km more.

Perhaps the only disappointment is that Jag says it has managed to eliminate the noise of the supercharger whine. Good for comfort, but we always rather liked that noise.

As well as the new V8, the XKR and XFR get a bunch of visual tweaks: the XFR has new bumpers and air intakes, a trunklid spoiler, quad tailpipes and 20-inch wheels, while the XKR has a new, more aggressive front end, LED rear lights and some clever underbody aero stuff.

The bit that's really got us excited, though, is a new Ferrari F430-type switchable electronic diff, which Jaguar promises can be set up for "easy drifting" when the traction control is switched off. Oh yes.