Edited by toxicdrift - 6/13/13 at 2:24pm
Seems that extra mid bass is still the flavor of headfi. That sig is not great for jazz at all with what happens to a string bass etc. Going back to your 1st post, ue18 and jh16 are clearly not the best choices from those makers for Jazz or, IMO, classical audiophile type listening. They do make others that fit the profile, One of the forum top guns very much like the UE personal reference monitors and jh13 but like all of us hasn't heard everything nor has your specific tastes.
How could anyone attempt to answer this question unless you've heard every last custom out there? And even then, sound preference is going to come into play. I don't get trying this answer this question. I can see better if some of you suggested what you thought were the top five or so (and only if you have actually heard them).
I just don't see how others can suggest what is the best CIEM for OP.
Also, I can't stress this enough : What sounds best for others might not sounds best for you. It's better to just listen to some demo units and use your own ears to tell which CIEM is best for you.