Check out:
www.VR3.com
I have no affiliation what so ever, but have known the owner for sometime.
Trey is his name and he mainly does Polk crossovers.
Great guy, exceptional work.
Polks respond very well to crossover mods.
Not my favorite speaker but doing the crossovers can take them to another level.
I redid some crossovers in some old crappy Polk RT10's I had, using the Sonic Cap Gen 1 caps, and could not believe the difference.