My car (a 2014 Mercedes GLK 250) did not come with CarPlay - it wasn’t even an option at the time.
But, after 5 hours (mostly spent struggling to get the extra wires to fit back in the dash behind the head unit), it does now. Fully integrated with the existing infotainment system and controls (no touchscreen). And it’s the wireless version, too!
A small thing, but I did it myself and I’m quite happy with it!