Well K1 and K3 should be different, K1 has same drivers as ubranfun, k3 knowles 30017 dual ba + dynamic.
seller shipped me K3 instead of K1, I'll share my impressions if no one else shares theirs by the time they arrive.
soundstage and details better in senfer? hm... Those were the strongest things about titans, they're sound were giving me a full headphone experience. Can you please listen to them again and make a quick comparison, mines just broke and looking for something similiar sounding, because really liked that kind of sound signature.