The R-designated big cat is back. And packing increased power, uprated looks and a host of expected enhancements over the standard XF, the R version will have its sights firmly set on de-throning the M5.

The R-designated big cat is back. And packing increased power, uprated looks and a host of expected enhancements over the standard XF, the R version will have its sights firmly set on de-throning the M5. These first spy shots, taken by a car magazine photographer, reveal the first prototype XF-R to not be a modified from an S-Type-based XF mule. They follow the car's Frankfurt debut and first production roll-off just yesterday.

Using a further tuned version of the V8 model's 416 hp 4.2-litre supercharged unit with higher boost pressures, the XF-R is expected to gauge power of nearer to 500 hp. With the 0-62 mph sprint from the present supercharged unit achieveable in just 5.4 seconds, expect M5 levels of performance for the XF-R. Uprated R suspension and brakes will feature in addition to an upgraded styling package.

In these spy shots, the game is given away for Jaguar somewhat clearly, with quad exhaust pipes featuring where the standard model boasts only two, a blackened front mesh grille and a noticeably lowered ride height. Residing under arches designed to cater for larger wheels, there are attractive 20" rims, behind which lie R ventilated discs. According to car's photographer, this XF sounded like no other XF he had ever photographed. Unsurprisingly, when approached by the magazine, Jaguar refused to comment.

With standard models hitting the market in March, the tuned XF-R won't be seeing the light of day just yet, with sales expected to start early 2009 with a possible late '08 motor show debut.

Jaguar XF-R Sports Sedan Spied