I used Upholstery screws and they have a washer type part that keeps the screw from pulling through the leather.Plus you need to drill through the plastic clip that the material is stiched to.This way there is no way it can pull out cause the material and the clip are really screwed to the metal part of the seat.Very hard to show but it works and look under or pull seat and fix.I have had no problums since I've owned my car from Early 2005(new).Hope it helps .Make sure that you make it through leather ,plastic ,and metal for good fix.It takes 2 screws on each seat.
