I like performers in room presentation, modded a number of speakers and crossovers over more than a decade. First off, electronics, pre's, amps, sources are greatly responsible for sound staging, so that good place to start. As for crossover mods, my intention with these mostly for gains in resolution, transparency, more natural timbre, wasn't looking for sound staging presentation to change per se. Having said that these mods did affect sound staging to some degree. Generally, I've heard more dimensional images, larger sound stage such the illusion of performers in room much greater. So, speaking in generalities, SET amps, DHT pre's and physically large horns do it for me.
As for specifics with crossover mods, I've used Duelund, Jupiter, Audyn caps, all very nice, specific models in these brands will give you exact voicing. For what its worth, at present using combo of Jupiter VT with Audyn True Copper Max, Jupiter VT bypassed with Duelund Silver bypass cap. Jupiter VT is a more laid back cap, Audyn more up front. Also love the Jantzen air core inductors, solid core on mids/bass, wax impregnated litz on tweeters, both top notch, may amaze you depending on current inductors. Internal wire important as well, I like Duelund tin plated copper. By the way, these on Klipschorns, custom drivers, Volti tractrix horns, custom tweeter baffles. I also modded Merlin VSM, Omega, and others in the past, always to good effect.