I have a 2012 XF 2.2D, bought from new. Here is my apocryphal tale.
I have always feared the day that I got a puncture and it finally occurred a couple of weeks ago. I returned to my car after 2 hours away and found a wheel half deflated.
I decided not to employ the foam, but reinflated using an electric pump I keep in the car - just as well because when I got home (2 miles) I found the puncture was in fact a tear at the base of the valve, with air hissing out. Since the tyre was quite old, I got Halfords mobile service to fit 2 new front tyres at home the next day (good service). The fitter said the foam would not have worked and just have made a mess on the drive - and rendered the tyre unusable (they cannot remove the foam).
Next problem was that he could not remove the other front wheel to fit that new tyre - one of the nuts sheared off due to rust - the same thing happened at ATS last year. Both times I have had to go to a a garage and pay for the wheel to be removed (doubling the cost of tyre replacement). Both they and Halfords told me that Jaguar wheel nuts are well known for failing like this - so I decided to have them all replaced with brand new ones.
I also decided to get a spare wheel and, following the recommendations on this blog, went for a full size alloy over the space saver. I found exactly my wheel size (R18 245 X 45) and design on eBAY for only £109 - it is in good condition, tyre with plenty of tread and fits under the boot floor once the plastic cut out insert containing the foam repair kit is removed. The spare is also very heavy and requires some muscle (I am quite fit for my age!) to remove and fit it. I guess the spacesaver is lighter - but has a limited range and speed.
I also ordered a jack plus brace kit "suitable for the Jaguar XF". The jack is a scissor type and raising the car off the ground took a lot of time and effort - I should have paid more for a pneumatic type.
The single arm brace was a joke, could not shift most of the nuts and then sheared off completely. I then tried my socket set, which also could not shift them. The garage was not surprised and explained that the wheel nuts are tightened tight to 125nM. This requires a long handled wrench, ideally a torque wrench, so they can then be re-tightened correctly. I just bought a Fourobber torque wrench on Amazon for £37 which does the job very well.
So I just did a dummy run with all my new equipment and wheel - It took nearly an hour and I am knackered. If I get puncture out on the road, especially at night or in bad weather I will call my rescue service and let them put on the spare!
Hope this helps
Steve G
