Won't the adjusters and mounting brackets from your old seats bolt up to the new seats? Car manufacturers, for the most part, do not manufacture their own seats, and the adjusting tracks that make the seat go forward and back have standard dimensions. The only thing that changes from car to car are the brackets that mount to the floor. What are the dimensions for mounting the tracks on your new seats on the bottom?
No one lives forever, the trick is creating something that will.