All of the front clip parts are interchangeable. If you use the bumper from a slo, you need to also use the header and headlights. If you want to keep the sho fenders, you need to use the sho/sable turn signals. The lights have a different angle, but will work with the slo lights.
The only real difference between a sho front clip and slo is the bumper cover, sable bumper, fenders, hood, header and lights. I been fixing mine with sable parts