I wanted an 8 pole filter for 0Hz offset to allow true dual rx without the 'slow beat' audio problem.
I had the option to pay $90 extra to SWAP the stock sub rx 2.7K 5 pole for an 2.8K 8 pole and of course I'd have to spend another $125 to match it in the main rx.
In the end I paid $125 extra, kept the stock 2.7K 5 pole and bought another 2.1K 8 pole . I already have a 2.1K 8 pole in the main rx, so having one in the sub rx will allow me to lock the rxs together with a vert and a horiz antenna and listen to both at the same time without 'audio beat'. I also paid $30 extra to get the new 2.7KHz matched (-0.93KHz offset) with the existing one. So hopefully I can get the best of both worlds for not too much outlay.
I recon the 2.1KHz 8 pole roofing filter will be sufficient for SSB/DATA/CW in the sub rx. I'm sure the DSP filter width can more than handle DATA/CW inside a 2.1K roof. SSB through the 2.1KHz is fine (better if the shift is adjusted down 200Hz or so), but it excels on a busy/noisy band. Even in this configuration it should still beat most other radios out there.