"Infotainment upgrade" isn't really applicable to the 2020/2021 Model X (I assume you're thinking about a Model X because you posted in the Model X forum, but you didn't say specifically). Basically the infotainment upgrade updates older MCU1 cars (using the original Tegra processor) to MCU2 (using an Intel Atom processor). Model S/X after about 2018 or so already have MCU2, so the car you're looking at doesn't need the infotainment upgrade.
Let me echo
@Nizzore's plug for being able to customize the data shown on the instrument cluster. It's been quite useful on my 2015 Model S. But on the Palladium Model S/X (what many people refer to as "refreshed"), that functionality is no longer there. Yet another instance of "newer isn't always better".
Bruce.