Getting rather OT at this point, but the rear seat heaters are in place and wired up along with the ambient lights (purely software locked), but oddly enough the extra speakers are in place and NOT wired up. Several SR+ owners have confirmed this in doing their own wiring. The entire wiring harness for the extra speakers, along with the subwoofer are physically absent.
That being said, I would pay upwards of $1k to $2k for a "Premium interior upgrade" if Tesla sent out a mobile tech, installed the missing harness and subwoofer, and unlocked the software locked seat heaters and ambient lights.