Clarity and sound stage is the main priority for me.
Here is a list of my current contestants. Feel free to suggest other IEM
Logitech UE 900
Stay away from shure, the I have the se535, the soundstage is great but the details are so-so, the se535 with their forward midrange push the music in your face but not the details themselves, the sound doen`t carry much information, its hard to put into words, but they skip over a lot of micro details, still nice sounding but maybe not what you`re looking for, I recommend the PFE232`s, they effortlessly portray fast music, with great speed and detail but also bass impact, soundstage width was probably the best out of all the iem`s I have tried (including ie8), and depth was great too but not as good as ie8`s/fx700, isolation is not too good with the PFE though so be wary of that, soundwise, they are only bested by $1000 flagship iem`s.