yeah you need the box for the belts to work but it's and easy wire up.
96-7-8 sebring convertible seats with control box fit fair. youcan also use up to 2000 sebring seats but you have to get the wiring and box off of an 96-7-8 since they moved it to the computer.
you do have to do some floor mounts. I use 1 1/4 angle tacked to the floor and 4x4 plates welded to the bottom and bolted together for a solid mount on mine.
I have a pic somewhere showing the black box that's underneath the console of the sebring , but if you follow the wires from the drivers side power seat it will lead you right to the box and get it all . later you can use or discard the extra wires if you don't use them.