My HK USP 40 came with Trijicon "night sights" (though, after 21 years, they probably need to be replaced). The only thing I've done to this pistol was to put a Pachmayr slide-on grip with molded finger "indentations" over the stock grip. This is a strictly personal "improvement" because, although the Pachmayr grip fits my largish hand well, it's not for everyone.