I want to take the rear interior side panels out. Do I need to remove the rear upright seatback? If so, how do I do it?
Yes, you need to remove the rear seat back. The seat back is hung from a couple of "hooks" at or near the top of the seat back and are secured at the bottom by one bolt on each side in close proximity to the seatbelt attachment points. Once the bolts are removed from the bottom of the seat back, push the seat back up from the bottom.
T-50 Torx bit needed for the seat bolts at the bottom...they might be really difficult to remove, even with an impact gun. If so, you can try soaking them with penetrating oil overnight. Otherwise they might need torched from the bottom (not fun and potentially dangerous). Optionally, you can cut the metal tabs around the bolts to allow the seat back to be free.
I just needed to get the upper pieces out. I was able to get them out without taking the rear seatback out.
Thanks guys for the quick responses guys.
I never took my seat out to remove my side panels