I was under the impression that the slides and frames go through the mfg. process together in order to ensure the tight tolerances. If true, then getting an extra slide as an aftermarket item might be quite expensive if one had to return the gun to the factory for hand-fitting. At any rate, aside from the different look of each slide, I don't see a point to having both sighted and sightless models. Get an R9S, ignore the sights for point-shooting, and use 'em for more precise shot placement. The sights are truly snag-free, so this should not be a factor. But since I prefer having the option of sights when I want them, I guess my bias is showing.