I am currently replacing the rear floor pan (along with much of the front) on my 95 D1. The mounts for the center rear seat belts had the bolts broken off in them and attempts to remove them cleanly eluded me. There is not an abundance of spares in my area so I was wondering how bad an idea it would be to simply weld a grade 10 nut to a piece of 1/4" plate and in turn weld that to the bottom of the floor pan and run a 1/2" grade 10 bolt to hold down the belt? I cant see that being any weaker than what was removed. Pic of the factory assembly is in the attachment