Joker,
It seems to me that I finally understand what i want and i finally decided. I will pick the PR401.
Hearing to CKM55 today with very attention i see what i like on their sound - is the sparkle highs and the bass (i don't know if is mid bass, but is from drums of bands like Pink Floyd, Dire Straits, Eagles...). But i hear too the harsh highs and sibilance on them, and now i understand what these words mean, hehehe. It's good to see that my ears have detected these weakness of my IEM, because i while back i can't hear this things or ignored it. I'm very new to sound and don't know very much.
I look to emphasis on treble, bass and great instrumental separation. The ECCI PR401 seems to have this and i have a feeling that i don't will be dissaponted with them because of good reviews around there, include your review. It's is proballly much better than my actual IEM, i have no doubt of that.
Thank for your multi-review, it's the most complete review i see around here.