Jaguar has made its spiciest XFR saloon even more super with the addition of a not-very-PC "Speed Pack".

Designed for buyers who are worried 155mph isn't quite fast enough, the new upgrade increases the top speed to 174mph. Perfect for the Autobahn, not so much the M1.

Aimed at après-golf posers, the Speed Pack costs an additional £2,750 over the standard car's £65,380 list price.

And just so your golf course buddies know you shelled out a little more, Jaguar has helpfully added some styling additions so they'll know you went for the faster version.

Speed Pack versions get sporty styling upgrades which include a new front aero splitter and racy rear wing.

Jaguar technicians have also recalibrated the engine and gearbox settings to make sure the car is well suited to the upgrades.

Strangely, the Speed Pack option doesn't add a power hike, though – output from the 5.0-litre V8 remains at 503bhp. It comes with an eight-speed automatic gearbox and a stop/start system to improve fuel economy and CO2 emissions. In fact, the combined cycle MPG figures have improved by 11 per cent and emissions are down by more than eight per cent.

Jaguar has also released prices for 2013 versions of the XF saloon. The range starts at £29,940 for the XF 2.2-litre diesel SE - up £450 over the 2012 model's price - and rises to £65,380 for the standard 5.0-litre V8 XFR.

Watch Jeremy Clarkson test the Jaguar XFR on Top Gear below