I think if Tesla would allow the PUP option then it would have to be probably done by either their own or Tesla-approved body shops because SC's will simply not be able to handle these given that they are already overwhelmed. If anyone who wants the PUP or at least certain features like heated steering or music system, and you have a scheduled visit to the SC, it might be worth asking them if they can let their approved body shop install the upgrades. If there are enough people asking them about this & the SC informs upper management, they may consider it at some point to provide this option to the old timers; it's a long shot, but you never know with Elon!