07-31-15: Kr4
Passively bi-amping with another CA-2200 will get you less than 3dB more output. Using the CA-M600 will get you almost 5dB and, probably, more head room.
I won't stir the hornets by commenting on bi-wiring but I use shotgun cables on my 800D2s, fwiw.
Good advice. I plan on upgrading from an integrated amp to separates later this year which will give me MUCH more power and control. I could have invested in mono's, but prefer to keep my system balanced. Like Kr4, I use shotgun cables (Jorma Statement). FWIW, my goal is to keep my box count down & focus on quality over quantity, though power amp numbers do matter with a moderately tough load.