Time for another update: After some weeks of waiting, finally the Bride MO seat rails arrived. After studying various solutions, and by wanting to keep it Japanese, I ended up with the bride MO type rails: A first check to see if they fit in the car, showed it all works well: Next step: Fit them to the seats: I used some existing holes, but need to drill a few new ones. So this is all just a quick mockup to see if it all fits: First result looks good. One problem I noticed is that the door handle will touch the seat so it needs to go slightly higher…