Subwoofer for Dynaudio Confidence 5- 2 Channel

Does anyone have a reccomendation on a good pair of subwoofers for the Dynaudio Confidence 5 for 2-channel. I currently have one James EMB1000 and a James EMB1200 that I planned on using in a second and third room. Would it benefit me to buy a second EMB1000 or EMB1200 to match or is there something out there that will pair better with these speakers?

When I had C5, I paired them with Rel Stadium III before w/o much success. As good as Rel was, C5 bass details were lost and I found myself constantly adjusting Rel output depending on recording. At the end, I sold the Rel.

If Rel could not blend with C5, I suspect nothing will. C5 compounded bass and sealed enclosure made bass roll off slow and subwoofer blending difficult.