Hi Dan, I used the factory rails, used some flat plate 5mm thick to go between seat rails as to bridge the factory rails, and then welded on 40mmx40mm box section bolted up through that and into the base of the seat on both sides the flat plate bolts to the factory rails so you can still slide drivers side forward and back for adjustment pass fully welded as no slides, on the northside of bris vagas if you want to come have a look contact number is 0401717000