Cheapest mod so far!
So the seatbelts in the back were a pain in the butt because it was pretty much a two-handed job to get them clicked. I've seen others put a rubber tube, sliced along one side, around it to add some structural integrity.
What I've done is use a rubber door sill protector, zip-tied, and then wrapped with black gorilla tape to protect the seats from the zip-ties.
Now the kids and others who sit in the back don't get frustrated with getting the seatbelts done up.
Pics.....