So I've been doing daily drives to rack up some miles and get a good FSD score. It's really helped me get to know the car, and some of its foibles -- including, O Ye Bane of Banes -- rattles. Now, I'm a pretty forgiving person when it comes to car cosmetics. But rattles: rattles I cannot abide.
Early on I found that taping the latches, while helpful, wasn't enough to make my car sufficiently quiet. I noticed the backseats have some areas where plastic seemed to rub on plastic, and suspected this might be part of the problem.
So I broke out my trusty roll of gaffer's tape and applied some to both ends of each seat, plus one of the sides where the two seats meet in the middle. This has seemingly done the trick. Car was very close to dead quiet even over a stretch of bumpy road the last couple days.
Photos showing where I applied the tape, in case anyone is interested...
(1) Along the interface where the 60/40 seats meet:
View attachment 752435
(2) Interface where the edge of each seat meets the car:
View attachment 752436
Finally, note this was a semi-experimental application, so it's not nice and tidy, nor full-length in all cases. I may replace it, or I might leave well enough alone.