Basszilla - better with active bi-amp?

[spa317]

I have a pair of Dick Olsher's Basszilla speakers, open baffle Fostex 208 supplemented with an Aurum Cantus ribbon supertweeter, with Audax PR380 15" woofers in seperate bass bins. I use the Madison Sound built crossover for this design, and drive them with a 20w 845 amp. Quite happy with the sound, except wonder if actively bi-amping and running the big 15"ers with a more powerful sand/chip amp would give better bass control and make for a better sound. I was curious if something like a Behringer CX2310 might be a cheap way to find this out, or whether something like that might not be a good idea. Any comments on the active question or the Behringer would be appreciated. (Oh, the ribbon supertweeter are run passively using a Solen cap to cut their output below 15k, just above where the Fostex rolloff naturally)