Can confirm that Cardas Audio has a pair of 3.7 although I don’t know if that’s the main speaker in their listening room. The person I spoke with was interested in my upgrade project and wants to be alerted to any upgrades that become available for the 3.7.
Cardas hookup wire and binding posts were my final changes (and, perhaps, most extravagant expense). It was the icing on the cake, kinda snapped the sonic picture into a cohesive and clear soundscape.