Converting to different seats

1991 BMW 325i vert Recaro Sport custom covered in two tone.
Four point harnesses on both.
They adjust like 11 ways, and slide way forward when tilted to let someone in the back.
They are originally made for a flat floor, so we fabbed some special mounting frames for them

any pictures of how you made the mounting frames? I have a buddy who's into those old bmws and i could get some of those seats for cheap.