I installed the seat repair kit a few years ago, and it has stood up, no more sagging on the side, and the leathercreases although still thrre are much tighter.
I found that the seat frame on the side bolster had cut into the foam, thus making it sit lower, and also the lower seat frame cross wires had also cut into the foam. I used 3M 77 adhesive to glue the seat foam bolster back together at the cuts, and once I installed the seat repair kit jute under the seat, and the foam pieces under the bolster yo support it, that solidified the sides of the bottom cushion, and would keep the foam from being cut by the frame in the future
I used hog rings to replace the ones I removed from the back edge of the bottom cushion, but zip ties can be used as well,
There are great you tube videos showing how to remove the bottom cushion without much problems.
i removed the seat from the car, which is required, so no worries about the air bags, as the power is disconnected from them if the seats are removed.