Well, it really comes down to where is the strongest place. If you drill a hole right thru the floor at the corner near the rear piller that is about as strong a place as you will find. Use the large washers that come with the kit under the floor.
On the inner ones, again, right at the seat riser thru the floor is going to be hard to beat.
was overjoyed - until I noticed that there were no installation instructions. Where do I mount the seat belts? How do I get the bench seat out (assuming I need to) to put in the lap belts?