I would give it a try with passive bi-amping and see how it sounds. The benefits with a passive bi-amp include: increased power, improved damping and keeping the back EMF from the woofers with intermodulating with the upper frequencies. Plus, if you decide it isn't worth it after listening, you can go ahead with the sale...
If you like the sound you can employ an active crossover as well, either with your passive crossovers in place, or for the best effect, by removing them.
Greg
If you like the sound you can employ an active crossover as well, either with your passive crossovers in place, or for the best effect, by removing them.
Greg