As the name suggests, this will buy a new top speed, with the limiter lifted from 155mph to 174mph. That’s little use in the UK, admittedly, but there is more to the Speed Pack than that.
A new bodykit gives a more aggressive look and is claimed to aid high-speed stability, should you ever manage to get near 174mph. The new front splitter, rear diffuser and larger bootlid spoiler all help create a look that’s more befitting of the incredible performance, too.
The supercharged 5.0-litre V8 is no different to the standard XFR’s, so it boasts the same 503bhp output. What has changed – and this applies to all XFRs for 2013 – is the new eight-speed auto, which replaces the old six-speed gearbox. It shifts quickly and seamlessly, even when you take control with the steering wheel-mounted paddles, allowing you to make the most of the XFR’s mammoth amounts of torque. The 0-60mph sprint takes 4.7 seconds – the same as for the old car – but the new gearbox makes the performance more readily available. The Jaguar punches through the mid-range as soon as you put your foot down.
There are also a few changes to the Speed Pack models’ suspension, but unless you’re an absolute XFR aficionado it’s unlikely you’ll spot them. It still feels as comfortable as ever over flowing undulations, but can be caught out by the occasional deep pothole. That’s mostly due to the low-profile tyres, though.
Also new for the 2013 XFR – and not only for the Speed Pack – is stop-start. It helps improve fuel economy from 22.5mpg to 24.4mpg and cuts CO2 emissions from 292g/km to 270g/km. The system is a little jerky around town, though, so we ended up switching it off.
If you were to weigh up the benefits of the Speed Pack against its near-£3,000 price tag, you’d struggle to justify it. But, if you can afford the extra outlay, you’ll get not only an eye-catching new look for your XFR, but bragging rights over the Mercedes E63 AMG and BMW M5, too: those cars are limited to 155mph.