I've seen somewhere a picture of a fixture welded behind the seats to the tunnel to anchor the inboard seatbelts retainer. It looks like a good SWB solution. I need a outboard solution also.
If you know where it is I've tried for an hour to find it. If you have made a strong and clean solution for this issue I'd love to see a picture. As most of the SWB owners know the factory locations are not a good design.