I think you just slip them on either end of the back numper, and they're a snug fit between the bumper and the rear wings, so they stay in place without needing any extra mountings. Were Japanese export market P6s a thing, and did they have them fitted? If they didn't, surely you don't need them? What do I know!? I think they look good and would gladly buy those off you. I once tracked down a pair for my car, only to have one of them get split, or torn, rendering it sadly useless.