Awhile back I started modifying the floor pans around the outer longitudinal rails in order to fit the BMW E46 sport seats. To be more specific, the outer fixing rail of the BMW seat was hitting the curved shape of the floor and for this reason the seat was at an angle. To make the seats fit, I previously cut the curved shape of as necessary and just drilled the rail fixing holes to the floor pan. I finally got a round to finnish up the seat fixings. I made some reinforcement plates, which I welded on the bottom . I also asembled the parking brake lever to check clearance to the seat. The fitment is tight, but there is no collision in any position of the seat. Measuring from the surface of the seat to the ceiling at the up most position of the seat, the distance is 870mm and at the lowest setting the corresponding distance is 930mm. TeemuM measured 890mm with the stock seat, so I have to say I am quite happy with the outcome. I tried to position the seat as low as possible. For some reason there was an odd profile at the bottom of the other rail of the seat. This had to be cut off to allow the seat to sit level on the floor pan.
Here you can see the profile that had to come off.
After removal with an angle grinder, I applied some fresh paint on the rail.
The bolts I used are fine thread and made for the purpose.
This is the upmost position of the seat. The seat has all kinds of adjustments.
This is where I measured the distance to the ceiling.