Dave-
I just added the new M- sub sw5500 to my 5200front, 5000rear setup; this after looking at lots of sub options; the new M- subs sw1600, sw5500 now go as low as anything on the market - rated now down to 20Hz -3db; in my audio tests, I could find no bottom end to them for LFE, etc.;
I tried dual sw5500s with my setup and found it too much; I settled on a single sw5500(dual drives) in a setup similar to yours -

I would recommend them for M- setups, where previous models I could not;

Tatu - yes - they are non-ported;

ken