Perfect timing. had just bought a set of belts on ebay to do the same. I bought a belt assembly out of a 2008 Subaru Impreza sedan, middle rear seat. This assembly bolts to a flat package tray on a stock Subaru, like an E body. I am planning on running the belt through the defrost vent, and drilling two holes where needed, then welding some huge fender washers around the holes on the bottom of the tray to reinforce the mounting points. I was then going to use the stock mounting points in the floor. We only have one kid, so I am seating him in the middle. I will hopefully send pics to this thread when done.