Star of Jaguar’s stand at the Geneva Show was the XKR-S, a very limited-edition upgrade of the XKR. With the XF stealing the limelight, Jaguar has quietly been putting together a range-topping coupé that looks like it could be really rather special.Ostensibly a cosmetically enhanced XKR, changes are subtle but significant. The 4.2-litre V8 remains mechanically unchanged, and uses the same six-speed auto ’box with manual paddle shifts, but modifications to the engine management increase top speed from 155mph to a still-limited 174mph, making the XKR-S the fastest production Jag since the XJ220.Along with a 19mph increase in top speed over the XKR (0-60mph remains the same at 4.9sec), the XKR-S gets revised springs, dampers, anti-roll bars and a faster ratio steering rack. Ride height is lower, too, by 10mm, and there are also gets new Vortex 20in alloys. Brakes are the Alcon R units, optional on the XKR.Outwardly the biggest change is to the car’s styling – a new front splitter, rear bumper, spoiler and sill extensions give the XKR-S a subtly more aggressive look. At the back, you get a discreet ‘XKR-S’ badge.But while engine and chassis modifications are geared very much to increasing performance, Jaguar is keen to make the point that the XKR-S is still very much a luxury coupé. Inside, the XKR-S gets full leather trim, a specially tuned B&W Premium Audio system and ‘XKR-S’ branded detailsFinished in ‘Ultimate Black’ only, the XKR-S will be available in the summer but be quick with your cheque book if you fancy one. Just 200 will be made, for the European market only and in both left- and right-hand drive. Price is expected to be around £80,000.