If you plan to actively bi-amp the originals, you have to be mindful of the passive crossover's built-in notch filters (to ameliorate the cavity resonance of the planar transducers). BillD and Reese went down that road with Platinums:
http://thecarversite.com/yetanotherforum/default.aspx?g=posts&m=12933#post12933
Yes, and this site is a treasure trove of information. I am grateful to those that have shared all of there experiences. This is one of the great things about the on board DSP on the amps. Great flexibility with slopes filters Q and on and on. All settings can be saved as file to compare and tweak.