As part of an update of the Jaguar XK for the 2015 model year, the company has introduced two new special editions – the Jaguar XK Signature and XK Dynamic R – each with a different focus.

The luxury-focused XK Signature is powered by a 5.0-litre V8 producing 385PS and 515Nm of torque.

That’s power enough to propel the XK Signature Coupe to 60mph in 5.2 seconds (5.3 for the Convertible) and on to an electronically-limited 155mph top speed.  CO2 emissions are 264 g/km, with combined cycle economy of 25.2 mpg.

The more performance-focused XK Dynamic R benefits from the addition of a supercharger, resulting in 510PS and 625Nm.  The 0-60mph sprint is dealt with in 4.6 seconds while the electronic limiter is raised slightly to 174 mph.  CO2 emissions rise not surprisingly to 292 g/km with economy of 23 mpg.

Both models drive the rear wheels through a six-speed ZF automatic gearbox with steering wheel-mounted paddles.  The Signature uses a mechanical rear differential to help keep power in check, while the Dynamic R benefits from Jaguar’s Active Differential Control technology.

The Dynamic R goes on to add the Black Dynamic Pack: stiffer steering knuckles, uprated springs and dampers with 10mm lower ride height, and Jaguar’s Adaptive Dynamics system to help control body roll.

A body-coloured Aerodynamic Pack with front splitter, larger rear spoiler, rear diffuser and side sill extensions mark out the more performance-oriented model of the two, while a Performance Active Exhaust leaves passers-by in no doubt.

Inside, the Signature features Luxury seats in Ivory or Charcoal, suede headlining, Ebony veneer and metal sport pedals.

The Dynamic R, meanwhile, features Jaguar’s new diamond-sewn heated Performance seats in Ivory/Charcoal or Charcoal/Red with contrast stitching and 16-way adjustment with memory, plus black veneer, black suede headlining and metal sports pedals.

Both models also benefit from a reversing camera and 20-inch alloy wheels as standard.

Colour choices include Polaris White, Ultimate Black, Stratus Grey, Italian Racing Red, Dark Sapphire and British Racing Green.

Both cars are available to order now, with the Jaguar XK Signature priced from £54,950, the XK Dynamic R from £69,950.